How to choose CVT, DC and AT? Which gearbox is the best?
How to choose CVT, DC and AT? Which gearbox is the best?
In the article published above, why do the public treat domestic AT consumers differently? At that time, it was found that many people did not know the knowledge of the gearbox. Some people even said that the structure of the Dual Clutch gearbox is more complex and advanced than AT. That’s what the classmate said:
Dual clutch is evolved on the basis of at. AT has simple structure, low cost and low failure rate. It is not high manufacturing cost as you said. The double clutch structure is complex, so the cost is high and the failure rate is higher.
We have to admire the success of brainwashing. Today we will talk about the structure and characteristics of CVT, AT and Dual Clutch gearboxes, and how to choose them.
AT gearbox is generally called automatic gearbox, but automatic gearbox is a general term. The academic name of AT is hydraulic automatic gearbox. It consists of hydraulic torque converter, planetary gear and hydraulic control system. Its working principle is to achieve variable speed and torque through hydraulic transmission and gear combination. Among them, hydraulic torque converter is the most important component of AT gearbox and the soul of AT gearbox. Hydraulic torque converter is composed of pump wheel, turbine and guide wheel, which can transfer torque and clutch.
Because of the cushioning and adjusting speed of the hydraulic torque converter, the AT gearbox starts more smoothly, avoids the setback of clutch combination to a certain extent, and has better comfort of gear combination, but it can still give the driver feedback of gear shift. In addition, due to the role of hydraulic torque converter, gear shifting is not so direct, gear shifting speed is slower than double clutch gearbox, power transmission lacks a little direct sense. And AT gearbox can withstand the highest torque, so the power-intensive models generally use AT gearbox. Generally speaking, if you want to save your mind and enjoy driving, choose AT gearbox.
Advantages: Wide range of torque, smooth shift, a certain degree of driving fun, low failure rate, small size.
Disadvantages: complex structure, high cost, difficulty in research and development, relatively low transmission efficiency.
Dual Clutch Gearbox
Dual Clutch gearbox is a general term for gearshift operation through two sets of clutches, including dry Dual Clutch and wet Dual Clutch. Some people think that the dual clutch gearbox is an improvement of AT gearbox. In fact, it is not. The dual clutch gearbox is actually an improvement of manual gearbox. Dual clutch gearbox is like a combination of two sets of manual gearboxes. The two clutches control the connection and disconnection between two sets of gears and the engine respectively, so that “two gears” are ready when “one gear” is hung, and “three gears” when “two gears” are hung in advance. By analogy, the time interval of shifting is omitted to achieve rapid shifting. Generally, two clutches are connected with two input shafts. Shifting and clutch operation are realized by mechanical and electronic modules integrating electronic and hydraulic components. Compared with AT gearbox, the structure is simpler.
The prominent feature of Dual-Clutch gearbox is that the gearshift is direct and clean, but why the double-clutch gearbox will stumble at low speed is because of the hesitation of low-speed gearshift. When you slow down and speed up again, the double-clutch gearbox will fall into confusion. Whether it should be geared up or downshifted, then the stumble will occur. In view of this situation, adding a set of hydraulic torque converter can alleviate, such as the dual clutch mounted on Honda model. In addition, frequent clutch engagement caused by low-speed creep can easily lead to overheating of gearbox.
It is suggested that wet dual clutch can alleviate this phenomenon. In addition, due to the frequent contact of clutch, it is easy to bring wear and tear, and the maximum torque that dual clutch gearbox can withstand is limited, so many high-end models of Volkswagen use AT gearbox. Generally speaking, the smoothness and life of double clutch gearbox have made great progress, but there is still a gap compared with AT gearbox.
Advantages: fast shifting speed, lower cost, simpler structure, direct power transmission, high transmission efficiency, rich driving fun
Disadvantages: relatively poor ride comfort at low speed, large volume and relatively poor quality stability
The full name of CVT is Continuous Variable Transmission. Direct translation means continuous variable transmission, which is what we often call CVT. At first, it was through the rubber belt continuously variable transmission, then the gear transmission, then the modern steel belt continuously variable transmission, but in any case, it was through changing the diameter of two conical discs to change the speed.
The outstanding advantage of CVT gearbox is smooth shift, no power hollow problem, but also lack of driving fun. As for the fuel saving of CVT gearbox, which many people say is only theoretical, because CVT gearbox needs more powerful hydraulic pump. At the same time, due to the steel belt drive, the maximum torque that CVT can bear is also lower.
Advantages: smooth power, simple structure, small size, low cost.
Disadvantages: low torque, lack of driving pleasure, insufficient transmission ratio, only theoretically fuel-efficient.
These are the differences and characteristics of CVT, AT and Dual Clutch gearboxes. It is suggested that gearboxes should be selected according to their own conditions, and Dual Clutch is not recommended in congested sections. CVT is not recommended for high RPM speeding, but AT gearbox is the safest choice.