So, what role did China car companies play, or what role did they play? Is it really just the integration of supply chain? If self-owned brand car companies can't play an irreplaceable role in their own products, it will be difficult for China car companies to occupy an important position in the global automobile industry from the brand, but in terms of production, they will be seriously restricted by suppliers, not only it is difficult to get the latest products, but also the production capacity will be limited.
In recent years, with the improvement of independent brand technology research and development strength, we see that more and more China car companies have released their own core technologies, and the propaganda words heard at the new car launch conference have gradually evolved from the competition of suppliers to the competition of independent research and development technology. We have seen Chery's 4 1% thermal efficiency engine, Chang 'an Blue Whale power platform, Geely's CMA platform and so on.
There were frequent actions before the Chengdu Auto Show, and Haval Dog, a new generation of H6 and WEY were released one after another. P0 1 Great Wall Motor has brought a brand-new powertrain, 9DCT transmission and a brand-new 2.0T engine. Among them, the world's first 9-speed power shift is naturally the top priority. After all, transmission has always been the technical weakness of China car companies. Now the Great Wall has achieved a breakthrough in the field of dual clutch. Does this mean that the Great Wall has occupied the commanding heights of gearbox technology research and development?
Question: Why do independent brands only do dual clutch?
Limited by objective factors, dual clutch is the only way for China automobile enterprises to develop independently at this stage. As we all know, there are three kinds of mainstream gearboxes, AT gearboxes, CVT gearboxes and dual clutch gearboxes. First of all, the patent protection of AT gearbox is the strongest. If you want to develop it independently, it is difficult to avoid the grasp of patents by several major suppliers. AT the same time, the research and development threshold and manufacturing threshold of AT gearbox are also the highest, especially the accuracy required in manufacturing, which is beyond the reach of most independent car companies.
Compared with AT gearbox, CVT's research and development threshold is lower, but its main component steel belt is monopolized by Bosch, and this part of resources is currently mainly controlled by Japanese car companies. If CVT gearboxes are mass-produced by independent brands, the supply of parts will be limited.
Therefore, the only way for independent brands to break through the deadlock of independent research and development of gearboxes is dual-clutch gearboxes.
20 1 1, nine automobile companies, including faw, SAIC, Dongfeng, Chang' an, Geely, and great wall, jointly established zhongfalian investment company, and set up a joint venture with Borg Warner to conduct technical research and development on dual-clutch gearbox, hoping to overcome the difficulties of automatic gearbox.
Then, we also saw that more and more China car companies began to use powershift, and the Great Wall was one of them.
Question 2: Why did the Great Wall build the world's first 9-speed dual clutch?
Great Wall began to produce the self-developed 7-speed DCT gearbox from 20 17, and has produced about10.5 million units so far, which have been applied to various models of Great Wall. It can be said that Great Wall has accumulated a lot of production and R&D experience in DCT. In order to continue to make new breakthroughs in transmission technology, dual clutch is still the only way, and upgrading gear is also a difficult problem that the Great Wall must overcome.
For powershift, what we see most is 6-speed or 7-speed. Prior to this, the only 8-speed power shift in the world came from Porsche's PDK, which was a typical product at no cost. It is said that the cost of a gearbox has exceeded six figures. Previously, Volkswagen announced in 20 13 that it began to develop 10-speed DCT, but later stopped developing due to cost and technical reasons.
When the number of DCT gears exceeds 7, its volume will increase and the transmission efficiency will double. To solve this problem, we need to invest huge R&D and production costs like Porsche. But obviously, it is impossible for Great Wall to accept that the cost of a gearbox exceeds the price of a car, so what Great Wall needs to face is how to solve technical problems without increasing production costs.
Three questions: how does 9DCT solve the problems of volume and transmission efficiency?
Let's talk about grades first. Great Wall showed their research and development results at the press conference. A 9DCT gearbox has the same size as 7DCT, and the cost does not increase.
In order to control the size of 9DCT, Great Wall has applied many new materials and integrated technologies, such as synchronizer, hydraulic module, clutch module and electronic module. Great Wall redesigned the synchronizer structure of the new gearbox and applied many new materials for this purpose. Finally, compared with 7DCT, the axial spacing of 9DCT is reduced by 5.8mm, the weight is reduced by 2.6%, and the bearing torque is increased by 54%.
In addition, regarding the cost of this 9-speed dual clutch, Great Wall said that compared with the previous 7-speed DCT, it has no increase, but it also has higher low-gear bearing capacity, smaller gear ratio and better performance. However, the Great Wall did not make a more detailed interpretation of the low-speed transmission efficiency of the dual clutch this time, and the specific performance needs to be formally installed after 9DCT.
Four questions: What is 9HDCT?
In addition to 9DCT, Great Wall released 9HDCT gearbox used in hybrid system, which was upgraded by adding P2 module on the basis of 9DCT to meet the use of plug-in hybrid vehicles. It can also be applied to P4 structure with motor at the rear axle, that is, WEY? P8 adopts a mixed layout structure.
Great Wall At present, the Pi4 electric drive platform of the Great Wall adopts the structure of 6DCT+BSG motor +P4, and the upgraded Pi4 platform will adopt this route of P2 9HDCT+P4 in the future.
P2 structure adopted in 9HDCT of Great Wall can realize multi-gear use and various modes of pure electric, internal combustion engine and hybrid drive.
9HDCT gearbox can not only provide shorter shift time, but also provide different driving modes, namely: pure electric, normal, sports, comfort, energy recovery, four-wheel drive and sports+. In terms of fuel economy, 9DCT can improve fuel economy by 7% compared with traditional 7DCT, and 9HDCT can improve fuel economy by 70%.
Five questions: What are the highlights of the new 2.0T engine?
For a long time, the 1.5T engine code-named GW4B 15 and the 2.0T engine code-named GW4C20 are the main engines of Great Wall Motor. Although the power of these two engines is acceptable, the fuel consumption has always been the focus of user complaints. At the same time, although the power of the 2.0T engine is relatively strong, the material of cast iron cylinder gives people the feeling of being old-fashioned. As a result, Great Wall Motor released a brand-new 2.0T engine, code 4N20, with 9DCT gearbox.
There are two versions of 4N20 series engines: high and low power. This release is a low-power version code-named 4N20A, while the high-power version has been basically developed, but there are still some verification work to be completed.
For the new 2.0T engine, the Great Wall official explained it clearly. On the premise of improving efficiency and reducing emissions and fuel consumption, the power output of the engine should be ensured as much as possible. Therefore, the thermal efficiency of 4N20 series engines is also 38.3%. Although this is not the top level compared with the thermal efficiency of more than 40% of some Japanese brands, the thermal efficiency of more than 38% is already a very good level in independent, German and American departments.
In order to meet the first demand of developing this engine, with high efficiency and low fuel consumption, Great Wall has made four optimization improvements to the engine structure. 1, improve the compression ratio of the engine to 12, and make the port structure straighter to avoid knocking. 2. Use 350bar high-pressure overhead injector to improve fuel atomization effect, combustion stability, knock suppression and fuel consumption. 3. Adopt Miller cycle, close intake valve in advance, and maintain high expansion ratio, so as to increase work capacity and reduce fuel consumption. 4. The cylinder head is integrated with the exhaust manifold, which reduces the heat dissipation of the exhaust manifold and improves the energy utilization rate of the exhaust gas of the supercharger. 5. Through eccentric crankshaft design, reducing main journal and adopting low friction timing system, the friction work of this engine is reduced by about 5% compared with the same displacement engine.
In addition, in order to achieve the three goals of strong power, low emission and light weight, Great Wall has also carried out nearly 20 technical evolutions and transformations on the new engine, and finally made the maximum power of the low-power version reach 150kW, the maximum torque of 320Nm, the maximum power of the high-power version 180kW and the maximum torque of 385Nm. Compared with the current 2.0T engine with high and low power, the two versions are more dynamic.
With the popularity of a short film "Great Wall Motor hangs by a thread", the Great Wall in 2020 set an anxious tone for itself. The slogan of Great Wall Motor is "focus, professionalism and experts", and Great Wall also hopes to get the enterprise back on track through a self-reflection. The release of 9-speed powershift and brand-new engine has enabled Great Wall Motor to refresh its technical height again, which is also the first step to re-establish the brand image of "focus, professionalism and experts".
Text/Wang Geng
This article comes from car home, the author of the car manufacturer, and does not represent car home's position.