AMT gearbox - what is it ... AMT gearbox: description, function and technical characteristics

In order for the engine to drive the wheels with different torque, the design of the car provides a transmission. It can be either mechanical or automatic. In turn, both types have several subspecies. This is not only a DSG, but an AMT transmission. What is this transmission? How does it work? The answers to all these and other questions are in our article.

Characteristic

So, in our prospective car there is an AMT transmission. What it is? This transmission is a mechanical transmission. In it, the speed switching is carried out with the help of an eclectic control unit. The system responds to sensor signals and generates a reciprocal pulse, thanks to which the gears are switched. What is the characteristic of the AMT transmission? Reviews of car owners note that this transmission combines the convenience of the "machine" and the reliability of "mechanics". Unlike the automatic transmission, such a box requires less load, thereby reducing fuel consumption. At a cost, cars with AMT are much cheaper than the same models with automatic transmission, and in the same configuration. This is a kind of cheap analogue of an automatic box. Recently, AMT is installed even on budget cars. And it's not just about foreign cars, where the "AMT" gearbox is almost in the "base." Grant, Largus and other AvtoVAZ models have been equipped with such transmissions since recent times. Motorists have already assessed the convenience of using such a gearbox. It is really reliable and does not require constant clutch work, as on "mechanics".

Device

The design of this node assumes the presence of the following elements:

• Clutch system.
• Manual Transmission.
• Control drive.

What is the difference between AMT and automatic transmission? On all boxes of the first type friction clutch is used. Recall that the "automatic" uses a hydraulic transformer, or "bagel", which transfers torque due to the rotation of a special impeller and oil. The AMT robotic gearbox includes one or two clutch discs. The latter type of construction is used to reduce power discontinuities when switching to overdrive. At the heart of any AMT is a manual transmission. For example, German cars "Mercedes" uses a seven-step "tiptronic". On the "BMW" is installed six-speed transmission with electrohydraulic drive.

Types of drives

Depending on the brand of the car, the AMT transmission works differently. What does it mean? The design of the assembly may be a hydraulic or electric type of drive. So, let's look at how they differ.

Electric

In this case, a mechanical transmission and an electric motor are used. Such a drive has a big drawback. This is the speed of the gearshift. It is up to 0.5 seconds. This greatly affects the acceleration to "hundreds". A similar car on the "mechanic" will accelerate by 1-1.5 seconds faster. This is a significant difference. Due to the simplicity of the design, it is used on cars of the middle and budget segments. This is "Ford", "Fiat", "Citroen" and "Peugeot". Also do not forget about the domestic manufacturer. This "Vesta", "Largus", "Kalina" and other models of the company VAZ. AMT gearbox, the reviews are very positive, deserves a lot of respect. Due to reliability and ease of use "as on the machine", you can close your eyes to large intervals when switching. Well, for those who want to get the most out of a dynamic ride, there is an AMT with a different type of drive. We will consider it below.

Hydraulic

In the design there is a special tank with liquid, as well as additional cylinders (almost like in the braking system). Here, thanks to the use of hydraulics, the gearshift speed is about 0.1 seconds. On some sports cars, this figure can be 0.05 seconds, which is faster than the "mechanics". But, due to the use of the hydraulic drive, the system requires more energy. Accordingly, the construction becomes more complicated. Therefore, such boxes are placed not on budget cars. The exception are Volkswagen cars. It uses a preselective gearbox, which costs several times cheaper than conventional hydraulics. In other cases, such a transmission is put on cars "BMW", "Audi" and "Alfa Romeo".

Control

Monitoring of work and switching of speeds is carried out thanks to sensors. And both on hydraulic and electrical boxes. Here there are sensors ABS, control unit, as well as actuators. How it works? When the vehicle is moving, the sensors transmit a pulse to the electronic control unit, where the data on the oil temperature, engine speed and wheels, as well as the current position of the selector are processed. Further, the mechanism generates a control impulse, which goes to the eclectic engine. In the case of hydraulics, the unit transmits information to the solenoid valve.

Features of operation

Since the use of a hydraulic drive requires additional costs that affect the cost of the car, the electrically operated transmission can not be characterized by good acceleration dynamics. When switching, there are huge dips in the dynamics. But if the budget allows, you can buy a hydraulic AMT and switch like a real car. But even here everything is not so simple. As for robotic transmissions with a hydraulic drive, the reviews say that it regularly "eats up" the oil. We need to monitor its level. Yes, and it is very expensive.

Double clutch

Earlier in the article, we mentioned German Volkswagen cars with their preselective gearboxes. Recently, they have become very popular. And all thanks to the use of a double clutch system. Such a device allows you to quickly switch gears with minimal loss in dynamics. And all this without using an expensive hydraulic drive. Preselective they were named in view of the special principle of work. When the car travels in one gear, the second disc is already engaged in the next gear. Thus, when the machine needs to switch to increased speed, this process is performed as quickly as possible. Moreover, the system works not only to increase, but also to reduce the transmission. The machine very quickly "dumps" them during braking. The design of such AMT is very compact, which is especially important for small cars. There are two types of clutch. It's wet and dry.

Let's consider technical characteristics on an example of 7-step AMT. An electric pump is installed here. The volume of oil in the system is 1.7 liters. The peak torque of such a transmission is 250 Nm. This is quite enough for cars. But as for SUVs, they do not have such characteristics for overclocking. Therefore, a wet type of coupling is used here (the volume of oil is 6.5 liters). But the torque is an order of magnitude higher - 350 Nm. In any case, the use of a double clutch allows for speed switching without noticeable dips in the dynamics. Now this type of gearbox is used on German-made cars, in particular on Volkswagen. Also on vehicles "Skoda" is installed AMT gearbox. What it is? This is a six-speed robotic transmission with two clutches. The manufacturer gives it a five-year warranty.

Conclusion

So, we found out what an AMT transmission is. "Lada Vesta", equipped with such a checkpoint, will clearly be of interest to our car owners. After all, such a box on domestic cars appeared just recently. By the way, recently AvtoVAZ began equipping the "Priora" with a box of AMT.