You see this CVT gearbox is dried up and the steel belt is all rotten!
It's this gearbox again, and it's the problem again!
Look at this car again! It's not gone! It was sent over for repair!
Videos like these appear frequently on the homepage of my video site today, and if I'm a person who wants to buy a car, I'm going to be dissuaded by the video blogger's warning every minute.
But the CVT gearbox loves bad, is it really the pot of the CVT gearbox?
Looking at the current automobile market, it seems that only Japanese brands of grocery shopping cars use CVT gearboxes. Slightly more powerful, such as The German system, as well as many independent brand models, all use AT or dual clutch.
Does this mean that CVT is indeed too squeamish? Yes, but not exactly, because there is also a gap between CVTs.
The most common CVT transmission, that is, the CVT transmission used by most Japanese grocery shopping cars, is a cone disc steel belt transmission CVT transmission. Its main structure is active and driven cone discs, steel belts, hydraulic operating systems, etc.
Its transmission belt is mainly composed of two parts: steel belt and tapered steel sheet, the steel belt connects the tapered steel sheet in series to form a complete transmission belt. The tapered steel sheet and the taper disc are in direct contact and are driven by friction.
The advantages of this structure are obvious – the fuel consumption can be reduced by the gearbox, while the structure is simple and the cost is low, so the steel belt CVT gearbox is also the first choice for many family cars. There are countless models using this CVT gearbox in the market, especially the Japanese economy models are the most widespread. Like the CVT gearbox used in the Ralink 1.5L model, it can help Ralink reduce fuel consumption to 5.1L/100km, which is quite close to the hybrid. At the same price, models using dual-clutch transmissions consume at least 5.5L of fuel per 100 kilometers.
But the drawbacks of this CVT transmission are also obvious – fragile and unable to withstand too much torque.
First of all, the CVT gearbox relies entirely on friction to transmit power, rather than relying on gears like other gearboxes, so its power transmission limit is relatively low and cannot withstand large torque.
In addition, the steel belt CVT transmission is more fragile than the steel chain CVT transmission.
The steel belt CVT is similar to the engine belt, and the steel belt is stretched more during the transmission process. Like the belt of the engine, the steel belt of the CVT transmission will also fatigue, and over time the steel belt will have metal fatigue and break, and the vehicle cannot be driven.
That's why the video blogger at the beginning of the article yelled at this steel-belt CVT gearbox.
However, for the steel belt CVT gearbox, the manufacturer has a clear maintenance cycle, as long as the maintenance in accordance with the manufacturer's maintenance cycle specifications, the steel belt CVT gearbox should not have too much problem. Because the steel belt CVT transmission is a friction transmission, the heat generated during its operation will accelerate the aging of the transmission oil, so the replacement cycle of the CVT transmission oil is much shorter than that of other gearboxes. For example, the manual transmission oil replacement cycle of a Japanese car is 60,000 kilometers, while the CVT transmission is 30,000 kilometers.
The steel belt CVT transmission looks fragile, so what can be done to make the CVT transmission more durable? The answer is to change the structure of the CVT gearbox.
CVT transmission withstands high torque power output is usually in the initial stage, if you can reduce the torque of the steel belt at this stage, then you can delay the CVT gearbox recession time.
Toyota came up with a way to share the range of high torque through directly driven gears, which not only extends the life of the CVT transmission steel belt, but also obtains a better starting power response, which is the Direct-Shift CVT gearbox in the TNGA power sequence. C-HR fuel version, Lingshang, Camry, Velanda and other best-selling models are equipped with this gearbox, this gearbox and M20A engine pairing, not only power response, but also get a good fuel economy.
Or, if you think the steel belt is still unsafe, then replace the steel belt.
The CVT transmission used by Audi at the beginning of this century and the CVT transmission now used by Subaru are steel chain CVT transmissions, and the transmission body is not a steel belt, but a steel chain. The steel chain is formed after the squashing and relaying of the bicycle chain, compared to the steel belt, the amount of material used will be much more, although the steel chain will be heavier, but the strength of the steel chain itself allows it to transmit more torque.
Like the steel chain CVT used in the Audi A6 (C6) in 2005, with a multi-plate clutch instead of a torque converter, it can withstand a maximum torque of up to 280 N·m, and it took 370,000 kilometers to slip.
In addition, you may not expect that there is a family grocery cart that uses steel chain CVT, that is, Buick Veyron Pro.
The Veyron Pro is equipped with SAIC-GM's new generation of intelligent stepless transmission with a speed ratio range of up to 7.01, which can not only withstand the maximum torque from the engine of up to 250 N·m, but also achieve higher transmission efficiency.
At the same time, the gearbox also adopts a silent rolling friction sprocket system, an offset double-acting pump, a torque converter with a three-stage long-stroke shock absorber, a cascading heat exchanger and other innovative designs, which minimizes power loss and can lock the torque converter at lower speeds to achieve direct power input, which significantly improves fuel economy on the basis of ensuring power performance.
Prior to mass production, the CVT had completed more than 2.7 million kilometers of bench and vehicle testing, and had met GM global standards in terms of manufacturing process, without worrying about durability.
CVT is indeed the most important type of transmission in the automotive world, but now that electrification is threatening, the definition of CVT transmission is also changing.
The CVT transmission highlights "stepless transmission", that is, the correlation curve of engine speed and vehicle speed is smooth, and the transmission ratio can be instantaneously changed to a certain value in the range. According to this definition, various types of oil-electric hybrid systems with series functions can also be regarded as a kind of CVT. However, it does not have the transmission structure of cone disc, steel belt and steel chain, in order to distinguish it from the traditional CVT, many people call it E-CVT.
So E-CVT is actually very different from CVT, and now the mainstream hybrid system, The Japanese Toyota THS, Honda i-MMD, and the domestic BYD DM-i, Great Wall Lemon DHT, Geely's Thor Hi · X, can be regarded as E-CVT gearbox. But a closer look at their structure shows that they are dual motor structures, not cone disc drives.
After the hybrid is pure electric, at this time, the CVT gearbox built for fuel vehicles should completely withdraw from the stage, a single speed than the gearbox can do, why bother? But things are far from simple.
Like the engine, the power and efficiency of the motor are different in different operating conditions. In particular, permanent magnet synchronous motors have very large copper and iron losses at high speeds, reducing operating efficiency. So it really makes sense to build a CVT gearbox for the motor.
Now there are indeed parts manufacturers working in this direction. Bosch is developing a CVT gearbox for motors that can significantly reduce the losses generated by motors when driving at high speeds, thereby increasing the range. Of course, this set of motors with CVT gearbox is still for the use of family grocery carts, high-performance models, a gearbox is finished.
In fact, for the CVT gearbox, there are still many consumers who misunderstand it, such as its slow power output, easy to slip, low durability and so on. These misconceptions can become a factor for consumers not to choose CVT transmissions. Professor Ruben also had a misunderstanding of the E-CVT gearbox before entering the industry, and after a comprehensive understanding of the CVT gearbox family, he also decisively chose a model equipped with E-CVT, and is still enjoying the advantages of low fuel consumption and smooth power, which is very easy to use. So the CVT gearbox is not useless, its flash point is still a lot, as long as the maintenance is diligent, pay attention to its working state, it can also become a good helper for the driver.
Note: Some of the articles come from the Internet and are invaded and deleted