Recently, on cars of foreign manufacture there is an automated mechanical transmission. This is not a classic mechanics or a well-known machine gun. This is something in between. What is the AMT box? Reviews and automatic transmission device - further in our article.
Characteristic
This unit is a manual gearbox. But switching speeds here is automatic. The desired gear is selected by the electronic control unit. The computer responds to the sensor signals and generates a reverse pulse.
As a result, the car moves in the most optimal speed mode. This
gearbox (AMT) combines the economics of mechanics with the convenience of an automatic transmission. Now such checkpoints are installed on Skoda, Audi and Volkswagen cars.
About design
What does the AMT gearbox consist of? This transmission includes several nodes:
- Drive and clutch discs.
- Gear shift lever.
- Electronic control system.
Any robot uses a dual friction clutch. On ordinary mechanics, one disk is used. This design allows you to quickly switch gears to AMT. "Lada Vesta", which began to install robotic boxes, is much faster than its counterpart on the mechanics. And despite the fact that AMT does not have a clutch pedal. But not only Volkswagen-Audi and AvtoVAZ concern use such a box.
The AMT robot has long been installed on German Mercedes cars. It uses 7-jitronic. But German engineers took the automatic transmission as a basis, replacing the torque converter with a friction clutch. AMT's robotic transmission is also used on BMW vehicles. It is a six-speed gearbox with electro-hydraulic drive. A 5-speed gearbox is often used by Volkswagen-Audi.
Clutch types
There are several types of clutches for AMT boxes:
In the first case, electric motors are used. Such a drive has a lower response speed. Gear shifting occurs three to four times slower than that of a similar hydraulic drive. The switching time is from 0.3 to 0.5 seconds. But still faster than the automatic transmission.
As for the hydraulic drive, special cylinders are used here. They are controlled by a solenoid valve. This design is more complex, but at the same time has a quick response. The time for gear shifting at a gearbox with a hydraulic actuator is about 0.1 second. This AMT gearbox is installed on predominantly expensive cars. All the other cars of the middle and budget class are equipped with electric. Among them - “Skoda Octavia”, “Superb”, “Scout”, “Volkswagen Golf”, “Audi RS” and others.
About transmission efficiency
According to manufacturers, the robotic box is one of the most technologically advanced in terms of efficiency. It is about 97 percent. On an automatic transmission, efficiency is 90 percent.
As for mechanics, here this figure is almost the same as on the robot - 98 percent. Therefore, such machines are more dynamic.
Benefits
The main advantages of an automated gearbox:
- Low fuel consumption The machine on the "robot" spends almost as much as on the mechanics.
- A small amount of oil. Up to 4 liters of liquid should be poured into such a box. This is two times less than on a similar automatic transmission or variator.
- High clutch life. Since the switching process is controlled by electronics, not by the driver, the risk of burning the clutch is approaching zero (unless you intentionally press the gas pedal and the brakes at the same time).
- The presence of a semi-automatic mode. At any time, the driver can switch to manual mode and independently choose the moment when to switch to higher or lower gear.
Also, drivers note a high switching speed, even in automatic mode. And all thanks to the use of multi-plate clutch. When the car moves in first gear, the second disc is already engaged with the next.
And so on until you switch to the final one. If you drive at the highest possible, sixth or seventh speed, the drive will automatically be engaged with a lower gear. Acceleration to hundreds of such machines is comparable to mechanics. The box does not “stupid” during overclocking, and this is a big plus, according to car owners. Gear changes are made without a break in power and dynamics.
Transmission disadvantages
Reviews note the impossibility of flashing the gearbox to another mode. Also, when driving in traffic, car owners get very hot grip. To save the box from wear, you have to switch to Tiptronic mode.
You can not often ride with a trailer. The adhesion resource will be much less under such a load. In addition, the cost of maintaining the checkpoint is considered a big minus. Not all boxes fall under warranty. You have to regularly change the clutch disc. And since there are two of them at AMT, the price of service rises significantly. After 150 thousand, it is necessary to change the
friction clutches. Also, car owners are faced with wear on the
input shaft bearings. Such a breakdown is accompanied by a characteristic noise in the area of the checkpoint. With an increase in engine speed, it increases. This malfunction occurs due to the presence of metal chips in the mechatronics unit. Failure to be repaired in time will result in quick wear of the clutch discs. What is most sad, they do not sell new parts at AMT. All that can be done is to get at the parsing a more or less “live” box and remove the necessary details from it. On many Volkswagen cars, this transmission twitched, suddenly releasing the clutch. The reason was the mixing of the two types of oils that are used in AMT. The reason for this is a poor seal on the mechatronic unit. So, about 1 million cars for oil change were recalled.
About oil change
The manufacturer recommends changing the transmission fluid at least once every 60 thousand kilometers. The cost of new oil for AMT is 4 thousand rubles. You also need to buy a new filter for 500 rubles. Oil change is carried out at a specialized service and costs about 2200 rubles.
Automated Box Modes
During movement, the driver can set the gearshift lever to automatic or semi-automatic mode. In the first case, the transmission works, relying on the readings of the sensors and pulses of the electronic control unit. As for the semi-automatic mode, Tiptronic, which can be found on Mercedes cars with their automatic transmission, is connected here. There is a plus or minus switch on the gear lever.
On some machines, shift paddles are installed. Thus, the AMT gearbox no longer receives signals from sensors, but responds to the driver’s instructions. Some call this mode sports. The switching speed here is the same as in automatic mode. But here you can choose the speed at which low or high speed will be included.
Conclusion
So, we found out what a robotic gearbox is. As you can see, it combines the economy of mechanics and the comfort of an automatic machine. But in terms of service, this transmission is one of the most expensive. Often, the cost of repairs reaches 1-1.3 thousand euros. If the vehicle’s mileage is less than 150 thousand (or five years), the dealer is responsible for the repair. But what will happen when the car "flies" with a guarantee? All problems and maintenance costs are borne by the car owner. Knowing the problems with AMT, such cars are difficult to sell in the secondary market.