Before answering why Japanese cars are keen on using CVT gearbox, we must first understand who invented CVT gearbox. In fact, CVT gearbox was not invented by the Japanese, and the design of CVT actually originated in Europe. The earliest CVT gearbox used in automobiles was a Dutch automobile company named DAF. DAF has a transmission department, and the patent right of CVT gearbox is in this part. However, the design patent on this CVT gearbox was later acquired by Bosch in Germany.
In the 1990s, people began to realize the importance and trend of automobile fuel-saving indicators. AT this time, because CVT gearbox can find the best transmission ratio, that is, for the traditional AT gearbox, the third gear may be too fast and the fourth gear may be too slow, and CVT gearbox can reach the best transmission ratio of 3.5. Therefore, CVT gearbox had a unique advantage at that time, so that many European car companies began to adopt CVT gearbox at that time, such as Mercedes-Benz and Audi. Only later, many European car companies slowly gave up after using CVT gearboxes.
Japanese car companies began to use CVT gearboxes in large quantities, which should be in the mid-1990 s; Before, many European car companies began to slowly cancel CVT gearboxes because there was no suitable joint between the engine and gearbox. Centrifugal clutch was first used to combine the engine and CVT gearbox. This phenomenon did not solve the joint problem between the engine and CVT gearbox until the appearance of hydraulic torque converter, so Japanese car companies became more and more comfortable with CVT gearbox and began to use it widely.
Since the patent right of CVT gearbox steel belt is still in Bosch, Germany, CVT gearboxes produced in Japan at present, such as Jatco owned by Nissan and Aisin owned by Toyota, all need to buy Bosch steel belt when producing CVT gearboxes. In fact, the steel belt transmission mode of CVT gearbox has inherent limitations. At present, the torque of 30k g·m is already the upper limit; So CVT gearboxes are mostly used in the field of non-performance vehicles.
We have learned the reasons why early European car companies changed from adopting CVT gearbox to giving up, and why Japanese car companies are keen on installing CVT gearbox. But why does the American market, which carries the rise of Japanese cars, dislike CVT gearboxes in every way? This involves the problem of car habits. American consumers' car habits and road environment magnify the shortcomings of CVT gearboxes. The United States is vast and sparsely populated, and the speed of vehicles is fast. Consumers have innate requirements for the performance of cars, and this driving habit is very unfavorable to CVT gearboxes. On the other hand, there are many cars on the roads in Japan, which is actually more conducive to the popularization of CVT gearboxes. On the one hand, it is the road environment and car habits, on the other hand, it is a small car like K-CAR, which requires higher gearbox size. CVT gearbox can achieve a transmission ratio of seven or eight times, but its size is much smaller than AT gearbox, which is also a major reason why Japanese car companies prefer CVT gearbox.
After 1990s, people have realized that cars should save fuel, but Europeans choose to use complex engines or multi-speed gearboxes, similar to turbocharged direct injection engines, 8AT and 9AT gearboxes, to achieve the purpose of saving fuel, but the price is expensive. The Japanese concept is to simplify as much as possible, so they will not put too complicated designs on cheap cars, but use CVT gearboxes, even if they only match a very ordinary engine, they can achieve the purpose of saving fuel.
Of course, the above is more about the past of CVT gearbox. In fact, with the development of technology, the CVT gearbox in Japanese hands has also made up for many shortcomings in the past; Like Nissan Xtronic? CVT gearbox shares part of the transmission ratio through sun gear, which has the advantage that the powertrain can obtain higher efficiency; Toyota's direct-drive CVT gearbox is also equipped with gears, which directly transmits power at the initial stage, and then returns to the steel belt to transmit power after acceleration. The advantage of this is that the vehicle can get better acceleration at low speed. For details, please refer to the CVT gearbox analysis of C-HR or Yize.
If the above technology is only an improvement in hardware, what great progress has been made in software? For example, combined with the characteristics of CVT gearbox and the driving characteristics of consumers, most CVT gearboxes can realize the shift experience similar to AT gearboxes through software simulation.
To sum up, we know why the Japanese liked CVT gearboxes in those days, and we also know that CVT gearboxes today make up for many deficiencies in hardware and software. Therefore, it can be said with certainty that most Japanese car companies have a positive and sustainable attitude towards the technical development route of CVT gearboxes.
This article comes from car home, the author of the car manufacturer, and does not represent car home's position.