AMT robotic gearbox diagram
AMT robotic gearbox diagram
It just so happened that there were a lot of complaints about AMT. Like, the driver and passengers nod when switching, the car becomes dull, and so on. The VAZ team listened and even offered several new firmwares, but the global update was announced only now.
No fundamental changes to the actuators were required. However, there are still innovations in the hardware - the control controller now has not one, but two boards, and, of course, a different transmission control program. So owners of robotic cars will not be able to simply come to the dealer and reflash the box.
What did they change?
The “traffic” mode, or, as it is officially called, the Creeping mode function, which appeared this year, has been retained. The driver simply takes his foot off the brake pedal and the car begins to roll forward. The speed in first gear is 7–8 km/h, in second gear it is 14–15 km/h. When you engage reverse, this mode also works - the car crawls at a speed of 5–6 km/h.
In this case, the Creeping mode function is turned off automatically under one of three conditions: if you open the driver's door while driving, if you move the selector to neutral or tighten the parking brake handle. That is, suddenly the car won’t move on its own.
The new AMT control program has reduced the gear shift time: from first to second and from second to third - by as much as 30%. They promise that the synchronizers will hold up.
The new AMT control program has reduced the gear shift time: from first to second and from second to third - by as much as 30%. They promise that the synchronizers will hold up.
About the design
What does an AMT gearbox consist of? This transmission includes several components:
- Drive and clutch discs.
- Gear shift lever.
- Electronic control system.
Any robot uses a double friction clutch. On conventional mechanics, one disk is used. This design allows for faster gear shifting on AMT. The Lada Vesta, on which robotic gearboxes began to be installed, is much faster than its manual counterpart. And this despite the fact that the AMT does not have a clutch pedal as such. But not only the Volkswagen-Audi concern and AvtoVAZ use such a box.
The AMT robot has been installed on German Mercedes for a long time. 7-jitronic is used here. But German engineers took the automatic transmission as a basis, replacing the torque converter with a friction clutch. The AMT robotic transmission is also used on BMW cars. It is a six-speed gearbox with an electro-hydraulic drive. The 5-speed gearbox is often used by the Volkswagen-Audi concern.
Advantages and disadvantages
The advantages of this transmission include reduced fuel consumption compared to traditional automatic transmissions. The presence of a manual mode allows drivers, just like with a manual transmission, to change gears independently. Reliability and demands on lubricants reach the level of manual transmission. The extended service life of the units and the entire mechanism as a whole is higher than that of a classic automatic machine.
Flaws
- High cost of production and repair
- Slow gear changes. This is solved by introducing a double clutch, which increases the price
- In city mode, the clutch receives more load. Service life is reduced. It is recommended to switch the selector to manual mode and navigate in traffic jams this way
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. With an automatic transmission, the efficiency is 90 percent.
As for mechanics, here this figure is almost the same as on the robot - 98 percent. Consequently, such cars are more dynamic.
Transmission Disadvantages
Reviews note the impossibility of flashing the gearbox to another mode. Also, when driving in a traffic jam, car owners' clutches get very hot. To protect the box from wear and tear, you have to switch to the “Tiptronic” mode.
Do not drive with a trailer frequently. The clutch life will be much less under such a load. In addition, the cost of servicing the gearbox is considered a big disadvantage. Not all boxes are covered under warranty. You have to change the clutch disc regularly. And since AMT has two of them, the price of service increases significantly. After 150 thousand you have to change the friction clutches. Car owners also face wear on the input shaft bearings. Such a breakdown is accompanied by a characteristic noise in the area of the gearbox. It gets stronger as the engine speed increases. This malfunction occurs due to the presence of metal shavings in the mechatronics unit. If the breakdown is not repaired in time, it will lead to rapid wear of the clutch discs. The saddest thing is that AMT does not sell new parts. All that can be done is to get a more or less “live” box during disassembly and remove the necessary parts from it. On many Volkswagen cars, this transmission jerked, suddenly releasing the clutch. The reason was the mixing of two types of oils that are used in AMT. The reason for this is a poor seal on the mechatronic unit. Thus, about 1 million cars were recalled for oil changes.
Clutch types
There are several types of clutches for AMT gearboxes:
- Electric.
- Hydraulic.
In the first case, electric motors are used. This type of drive has a slower response speed. Gear shifting is three to four times slower than a similar one with a hydraulic drive. Switching time ranges from 0.3 to 0.5 seconds. But still faster than an 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 it has a fast response. The time to change gears for a hydraulically driven gearbox is about 0.1 seconds. This AMT gearbox is installed on mainly expensive cars. All other middle and budget class cars are equipped with electric ones. Among them are Skoda Octavia, Superb, Scout, Volkswagen Golf, Audi RS and others.
