Equivalent to the engine industry, the fierce competition in the automotive transmission industry is no less than the entire vehicle market, AT, AMT, DCT, CVT, no matter what kind of gearbox, can find the corresponding industry giants occupy the leading position. Gatko, Getrag, ZF... Many people are familiar with the name. People who prefer controllability skim over these faces and their eyes are not on the car with the CVT automatic transmission.
Is CVT automatic transmission really useless?
According to the data provided by relevant parties, the acceleration of a 100-km model equipped with a CVT gearbox is not much more than a model equipped with a conventional AT or DCT. Many people feel that the so-called “meat†is just a subjective feeling of people. The reason for this feeling is that the acceleration of a model equipped with a CVT gearbox is linear, and unlike the other types of gearbox models, the acceleration curve is an “index functionâ€. In addition to this, it is considered that the infinitely variable transmission can be used in a large-displacement, high-power, and high-torque vehicle because it is limited by the maximum torque that can be tolerated by the use of a chain or a belt. In fact, with the optimization of the CVT structure and the advancement of material technology, the maximum allowable torque of the steel strip can reach 450 Nm, which is sufficient to handle the most of the passenger car operating conditions. As for the misunderstanding of the CVT gearbox, many auto parts suppliers around the world are making efforts to this end.
Recently, at the 4th CVT Campus Technology Forum on the theme of “Getting into the Green Futureâ€, students and teachers from various universities and colleges, relevant automobile and component companies in the automotive industry at home and abroad, and the industry Experts gathered together and they spoke freely and looked forward to the bright future of the CVT gearbox.
The technology is more mature and the advantages of CVT appear
In China, with the continuous maturity of automatic transmission technology, efficient CVT technology has shown significant growth in automotive applications with superior fuel economy, comfort, and cost-effectiveness.
With an infinite number of gear ratios, the CVT's unique transmission mechanism and intelligent electronic control system optimize the matching of torque and engine speed so that the engine can always operate in the most efficient manner, thus ensuring reduced fuel consumption and carbon dioxide emissions. The CVT provides uninterrupted power when shifting, thus ensuring 100% smoothness and optimum comfort, making it ideal for traffic in congested urban areas.
The continuously variable transmission is 10% higher in transmission efficiency than the conventional 4-speed automatic transmission. Although ZF and Mercedes-Benz have already launched a 9-speed automatic transmission, Volkswagen will even develop a 10-speed automatic transmission. Transmission efficiency is far less than that of previous automatic transmissions. However, anyone who has experienced 9AT knows that 95% of the time spent driving does not require 9th gear.
As a supplier of CVT pressure strip technology, Bosch has continuously invested and continuously innovated in the R&D and production of CVT to promote the further development of CVT pressure strips and to develop the right products based on the automotive market trends. The CVT manufacturer, Gartner, has also proposed the D-STEP concept at this forum. It aims to eliminate the "flesh" feeling of the CVT, so that it has excellent acceleration performance both in terms of actual performance and subjective feelings.
Fuel Consumption Regulations Promote the Popularization of CVT
There must be impetus behind technological progress. In the future, the global market's demand for low emissions and low fuel consumption will continue to promote its demand and growth. Zhang Hui, Bosch China CVT CVT Technical Director, said: “The market share of CVT is growing rapidly in China and North America. From a worldwide perspective, 1/5 of current automatic transmissions use CVT in the future. After this year, this share is expected to rise to 1/4.†This coincides with the prediction made by Toru Hatan, an analyst of IHS Automotive's powertrain, in 2013. He once said: “In the next six years, the continuously variable transmission will gradually Grab the share of other types of automatic transmissions."
The initial batch production of the CVT model was the Subsity Justy model launched in 1987. Until 2003, Nissan introduced the Muranocrossover model, making the CVT popular. It is not surprising that the success of CVT stems from the Japanese market. Japanese drivers have always preferred automatic transmissions. Moreover, the CVT's very compact design can reduce the production cost, and it also makes the CVT perfectly match with the city's small car, which has an advantage in the densely crowded Japanese city traffic.
With the success of Japanese models in the North American market, CVTs have become more and more popular. They have also led to China and other Asian countries. However, they still lag behind in Europe. The reason is mainly due to the fact that Europeans are more inclined to manual transmissions than other regions. Sport driving experience. However, this will gradually change. As automakers are under pressure to reduce overall vehicle CO2 emissions and European consumers are increasingly confident about advanced CVT technology, there will be more and more CVT models in the European market.
CVT is very suitable for new energy vehicles
The new generation of continuously variable transmission from Gatko, the Japanese gearbox manufacturer, will reduce the gap with the dual clutch gearbox in terms of mechanical losses. Engineers will achieve this goal by reducing the friction between the oil pump and the bearing and reducing the oil droplet splash during gear rotation. Its CVT8 continuously variable transmission released in 2012 has been used in the new Nissan Altima. Compared with the previous generation, its fuel economy has increased by 10%. According to foreign media, Jun Shiomi, chief engineer of the CVT8 continuously variable transmission, said that he has now embarked on the research and development of the next-generation continuously variable transmission. At present, GatTech has two CVT8 continuously variable transmissions that can be applied to all kinds of vehicle powertrains.
In addition, Gatky is developing a CVT for pure electric vehicles that will be used instead of single-stage gearboxes in pure electric vehicles, such as the Nissan Leaf. The choice of a single-stage gearbox for a pure electric vehicle by an automobile manufacturer is due to cost considerations because the cost of the electric vehicle itself is already high. The cooperation between the CVT and the braking energy recovery system in the electric vehicle is excellent and can extend battery life through good economics. In addition, the CVT allows the motor to operate at maximum efficiency over a wider range.
Although the industry has never stopped debates over the superiority of AT, DCT, and CVT, in fact such disputes are meaningless because "according to the road conditions and driving conditions in different regions, there is always a more suitable gearbox." . With the introduction of the latest fuel efficiency regulations in China and other countries, the CVT can not be fully recognized by the market with excellent smoothness, economy, and acceleration performance. This is what every company and the main automobile models need to pay attention to.
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