Automatic transmission, CVT, robot - what's the difference?

Today, automatic transmissions are being installed in an increasing number of new cars. And on some cars, for example, only an automatic transmission is installed, and the buyer is not even offered a manual option. Even before buying a car, it is useful to know what automatic transmissions are and what their differences are.

Today there are three types of “automatic machines”

— “ Normal ” (torque converter),

- Variable speed drive

— Robotic (robot).

It is important to know the differences between them not only when buying a new car, but also a used one - to an ignorant buyer, a dishonest seller can easily pass off a CVT or “robot” as a classic “automatic”. So let's find out what the difference is between them and which gearbox is better to choose? Let's start with a regular machine.

Robot

A robotic gearbox is something between a “mechanical” and an “automatic”. The main difference between a robot and a manual one is the presence of a control unit, which shifts gears for the driver. And here there is also some pause when switching.

In addition to the pause described above, the robot has other disadvantages:

— Jerks and jolts when switching

— Slow response

— The need to turn on the “N” mode when stopping with the engine running (otherwise it can overheat)

— Impossibility of towing

As you can see, the robot has a lot of shortcomings. But it’s not for nothing that there is a demand for cars with a robot - after all, this transmission has the following advantages:

- Low price compared to an automatic or CVT

— Low fuel consumption

But still, robots are a thing of the past, and they are gradually being replaced by more modern developments, namely...

Drawing conclusions

What are the differences between a variator and a robot, and which of these gearboxes is better? A variator is a type of automatic transmission, while a robot is still closer to mechanics. It is on this basis that you should make a choice in favor of one gearbox or another.

Preferences in choosing a gearbox usually come from the driver himself and are based on his requirements for the car, as well as his driving style. Are comfortable driving conditions important to you? Then choose a CVT. Do you prioritize reliability and the ability to drive in difficult road conditions? Your choice is definitely a robot.

When choosing a car, the driver must personally “try out” both transmission options. It should be remembered that both the robot and the variator have their advantages and disadvantages. The purpose for which you plan to use the car will also help you make your choice. In a calm city rhythm, a CVT will be preferable to a robot, which simply will not “survive” in endless traffic jams. Outside the city, in difficult road conditions, when driving at high speeds or when driving sportily, a robot will be preferable.

Reselective transmission

The shift transmission is a second generation robotic transmission. It also goes by the name DSG , which is an acronym for Direct Shift Gearbox.

This box is the most advanced currently available. It has two clutch discs - one shifts even gears, and the second - odd.

The key feature of the DSG gearbox is that there are two gears in this box at all times. But only one of the two disks is connected to the engine, and the second is at the ready. As soon as the gear change occurs and the first drive is disconnected, the second one is instantly connected. It takes less than a second to change gear, and the smoothness of the DSG can be compared to a CVT.

However, the DSG also has its drawbacks. This transmission has a very complex design, resulting in high maintenance costs. In addition, even a large service center is not always ready to undertake the repair of such a box, and the repair itself is sometimes simply impossible. Therefore, in case of breakdowns, often the only solution is to completely replace the transmission or, at best, replace the electronic control unit. Another disadvantage of the DSG gearbox is the overheating of the clutches after a long drive, which can cause the car to jerk when changing gears.

Automatic, CVT, robot or DSG - which is better?

So which box is better to choose? This question can be answered by knowing the financial capabilities and driving habits of the car buyer.

However, most motorists still agree that a classic torque converter automatic is the optimal solution today. Despite the smooth running of the CVT gearbox and the efficiency of the DSG box, the CVT has a low resource and is installed only on cars with small-volume engines, and the DSG, due to the novelty of the technology, often turns out to be beyond repair.

Well, what speaks in favor of a conventional machine gun is the fact that its design has stood the test of time and is currently the most “tested” and reliable, and many of its shortcomings are not critical.

CVT or automatic - which is better?

After we have studied the strengths and weaknesses of automatic gearboxes, we can return to the question of what is better - a CVT or an automatic? But there is no clear answer to it.

Supporters of automatic machines rely on the fairly high reliability of such boxes, their convenience, the presence of various operating modes and the ability to switch independently. They criticize CVTs for noise in the cabin, low service life and periodic overheating, which directly leads to expensive repairs, or even replacement of the gearbox.

On the other hand, supporters of the CVT directly say that after driving a car with such a gearbox, even the smoothest automatic transmissions seem “jerky.” In addition, CVTs have lower fuel consumption. As for the higher cost of repairs and frequent breakdowns, many continue to turn a blind eye to these aspects.

However, it seems to us that in this fight preference should be given to the classic automatic transmission (torque converter). Yes, the CVT is smoother and softer, and the DSG is faster and more economical. But CVTs require a calm driving style (and their reliability leaves much to be desired), and the disadvantages of preselective gearboxes, in our opinion, significantly outweigh all their advantages.

If you soberly assess the situation, it becomes clear that today, among all types of automatic transmissions, the torque converter design is the most mature and reliable, and many of its shortcomings have either already been eliminated or are not critical.

Pivot table

In the end, I want to put all the pros and cons in a table and see who scored the most. Plus is one point, minus is no point, plus and minus are 0.5 points.

Now we are watching the video version.

Good old hydromechanical gearbox

Examples of use: almost the entire range of Korean and American brands, as well as relatively powerful cars from other manufacturers.

It is a stepped planetary gearbox connected to the engine through a torque converter. The selection and switching of planetary gears used to be carried out hydromechanically, but now ubiquitous electronics, together with the engine management system, determines which gear the power unit should operate in at the moment. The number of stages is constantly increasing, reaching nine on the most expensive cars.

MECHANICS

The oldest transmission, one of the first to appear in the automotive industry. This is not an automatic transmission, but a manual transmission (many call it “manual”).

PRICE is the lowest of all competitors, this transmission has been produced for a long time, the technology has been tested, there are not many components (low complexity), and therefore it is cheap. Repairing it is also not expensive; usually the clutch disc + basket + release bearing fail. To replace it with a set on our cars costs about 10,000 rubles. On expensive foreign cars that are equipped with a manual transmission, there is also a dual-mass flywheel , the originals are expensive (for example, VOLKSWAGEN can cost from 50 to 80,000 rubles), if you take analogues from 20 to 30,000. The box itself rarely breaks down, mostly the bearings fail , shafts. BUT going through will definitely be cheaper than automatic options.

COMFORT - this is where everything is bad (let those people who adore this gearbox not swear - mostly experienced drivers with 20 - 30 years of experience). If you take a beginner, he will choose any of the automatic transmissions, but not the manual transmission. This is explained simply, the mechanics have three pedals and you need to control how the car starts moving, but beginners have problems with this, especially uphill, in traffic jams, etc. This is where you can stall. With automatic transmissions this is much easier.

However, experienced people will say that I control the engine myself (speeds and shifts) and no automation decides for me! Also, the manual transmission accelerates faster than anyone else (looking ahead, I will say this is not true), with it you can climb through the mud and not be afraid.

Here, as they say, everyone chooses for themselves. A simple example: if you need to unscrew a self-tapping screw, you wouldn’t use a hammer to unscrew it, would you? Also, if you need a car for swamps and mud, then most likely you will take a manual rather than an automatic (just different tasks).

RELIABILITY - Here the torque is transmitted rigidly - from the motor to the wheels. The release of this rigid coupling and gear selection occurs by depressing the clutch pedal (the clutch disc moves away from the flywheel and basket). In terms of reliability, it has always been a leader; it is difficult to overheat and simply kill it (even if the oil leaks out of it , it will still run). That is why they like to use it for motorsports, for example, for rallies, mud (when UAZs crawl through forests and swamps), on many “sports cars” (even civilian ones), there are also mechanics, because it can handle high torques.

However, there are also negative aspects (for example, the clutch disc and dual-mass flywheel) - whatever one may say, the clutch disc will wear out closer to 100 - 120,000 km, change it along with the basket, release bearing, and if you also have a dual-mass flywheel , with it too (because its resource is just 100 - 150,000 km, of course it can be repaired, but that’s a completely different story). It is worth noting that many civilian cars have conventional flywheels.

In the end we get it. The gearbox itself is reliable, but in any case, you will need to change the attachment by 120 - 150,000 km.

FUEL SAVING – one of the most economical transmissions, since the connection to the engine is rigid, there are no parasitic connections such as a torque converter, the torque immediately goes to the wheels. You can also coast, put it in neutral, and go downhill (this also saves fuel).

POTENTIAL FOR DEVELOPMENT – Low. It seems to me that sooner or later it will leave the civilian sector and will remain only at a specialized level (military, special sports vehicles, etc.). For example, now, many manufacturers have high-spec cars only with automatic transmissions, but manual transmissions are installed only in the base or mid-spec models. Yes, and 6 gears is the maximum, you can add more, but why?

Robotic gearbox device

At its core, a robotic gearbox is a familiar manual gearbox, in which the clutch and gear shifting are controlled by electronics and servos.

Let's look at the “stuffing” of a robotic gearbox, in other words, its structure. And we will disassemble the double-clutch box, because we believe that these are the boxes that have the future, while single-clutch boxes will gradually become a thing of the past.

The biggest disadvantage of single-clutch gearboxes is the very long gear shift time, which makes driving a car uncomfortable and jerky.

The robotic gearbox consists of the following mechanisms and parts:

• The main working unit (analogous to a manual transmission), equipped with two pairs of shafts - primary and secondary (that is, four shafts in total), to which gear shift gears are attached. One pair of shafts is responsible for even gears and, accordingly, the gears of gears are attached to them - 2, 4 and 6, and the second pair of shafts provides odd gears and reverse gear - 1, 3, 5 and R. In addition, each pair of shafts has its own clutch (box with two clutches). It is also worth noting that the input shafts are on the same axis, that is, one shaft is located inside the other.
• Actuator units are servo-drive mechanisms (electrically or hydraulically operated). The electric type of drive is nothing more than an electric motor with a gearbox, and the hydraulic type of drive is a hydraulic cylinder controlled by electromagnetic type valves (hydraulic is more expensive, but faster and is used in the most advanced manual transmissions). Two types of actuators can be installed in a robotic gearbox - for shifting gears and engaging the clutch.
• The electronic control unit is a microprocessor that controls the operation of the entire robotic gearbox through external sensors and actuators. External (or input) sensors allow you to receive information about travel speed, engine operating speed, torque, oil pressure and transmit this information to the control unit. Execution mechanisms are designed to implement all tasks received from the control unit based on embedded programs. The unit itself is connected to the robotic box using an on-board computer.