What to choose: a robot or a variator
Content
The variator and the robot are two new and rather promising developments in the field of automatic transmissions. One is a kind of machine gun, the other is a mechanic. What is the best variator or robot? Let's make a comparative description of both transmissions, determine their advantages and disadvantages, and make the right choice.
All about the device of the variator
A variator is a type of automatic transmission. It is designed to smoothly transfer torque from the engine to the wheels and continuously change the gear ratio in a fixed range.
Often in the technical documentation for the car, you can find the abbreviation CVT as the designation for the gearbox. This is the variator, translated from English - “constantly changing gear ratio transmission” (Continuously Variable Transmission).
The main task of the variator is to provide a smooth change in torque from the engine, which makes the acceleration of the car smooth, without jerks and dips. Machine power is used to the maximum and fuel is consumed to a minimum.
Controlling the variator is practically the same as controlling an automatic transmission, with the exception of a stepless torque change.
Briefly about the types of CVT
- V-belt variator. He received the greatest distribution. This variator consists of a belt stretched between two sliding pulleys. The principle of operation of the V-belt variator consists in a smooth change in the gear ratio due to a synchronous change in the contact radii of the pulleys and the V-belt.
- Chain variator. Less common. Here, the role of the belt is played by the chain, which transmits the pulling force, not the pushing force.
- Toroidal variator. The toroidal version of the transmission, consisting of discs and rollers, is also worthy of attention. The transfer of torque here is carried out due to the frictional force of the rollers between the discs, and the gear ratio is changed by moving the rollers relative to the vertical axis.
The parts of a variator gearbox are expensive and inaccessible, and the gearbox itself will not be cheap, and problems may arise with its repair. The most expensive option would be a toroidal box, which requires high strength steel and high precision machining of surfaces.
Advantages and disadvantages of a variator gearbox
Both positive and negative aspects of the variator have already been mentioned in the text. For clarity, we present them in the table.
| Advantages | Disadvantages |
|---|---|
| 1. Smooth car movement, stepless acceleration | 1. The high cost of the box and its repair, expensive consumables and oil |
| 2. Save fuel by using the full potential of the engine | 2. Unsuitability for high loads and heavy road conditions |
| 3. Simplicity and lower weight of the box in comparison with the classic automatic transmission | 3. "The effect of reverie" when changing gears (although, in comparison with a robot, the variator "slows down" less) |
| 4. Ability to drive at maximum engine torque | 4. Restrictions on installation on vehicles with high power engines |
To prevent the device from letting the driver down during operation, the following conditions must be observed:
- monitor the oil level in the transmission and change it in time;
- do not load the box during the cold winter period at the beginning of the movement, when towing a car and while driving off-road;
- periodically check unit connectors and wiring for breaks;
- monitor the operation of the sensors: the absence of a signal from any of them can lead to incorrect operation of the box.
The CVT is a new and not yet optimized transmission system that has many drawbacks. Despite this, the developers and designers predict a great future for her. CVT is the simplest type of transmission both in terms of technical design and principle of operation.
Despite the apparent advantages that provide fuel economy and driving comfort, CVTs are rarely used today and, mainly, in passenger cars or motorcycles. Let's see how things are with the robot.
Robotic transmission
Robotic gearbox (robot) - manual transmission, in which the functions of gear shifting and clutch control are automated. This role is played by two drives, one of which is responsible for controlling the gearshift mechanism, the second for engaging and disengaging the clutch.
The robot is designed to combine the advantages of a manual transmission and an automatic machine. It combines driving comfort (from a machine), as well as reliability and fuel economy (from a mechanic).
The device and principle of operation of the robot
The main elements that make up a robotic gearbox are:
- Manual Transmission;
- clutch and clutch drive;
- gear shift drive;
- Control block.
The principle of operation of the robot practically does not differ from the functioning of conventional mechanics. The difference lies in the control system. This is done in the robot by hydraulic and electrical drives. Hydraulic elements provide fast shifting, but require additional resources. In electric drives, on the contrary, the costs are minimal, but at the same time delays in their operation are possible.
The robotic transmission can operate in two modes: automatic and semi-automatic. In automatic mode, electronic control creates a specific sequence for controlling the box. The process is based on the signals from the input sensors. In semi-automatic (manual) mode, the gears are shifted sequentially using the shift lever. In some sources, a robotic transmission is called a “sequential gearbox” (from the Latin sequensum - sequence).
Robot advantages and disadvantages
The robotic gearbox contains all the advantages of an automatic machine and mechanics. However, it cannot be said that it is devoid of disadvantages. These disadvantages include:
- Difficulties in adapting the driver to the checkpoint and the unpredictability of the robot's behavior in difficult road conditions.
- Uncomfortable city driving (abrupt starts, jerks and jerks when changing gears keep the driver in constant tension).
- Overheating of the clutch is also possible (in order to avoid overheating of the clutch, it is necessary to turn on the "neutral" mode at stops, which, in itself, is also tiresome).
- "Thoughtful effect" when shifting gears (by the way, the CVT has the same minus). This not only annoys the driver, but also creates a dangerous situation when overtaking.
- The impossibility of towing, which is also inherent in the variator.
- The ability to roll the car backwards on a steep incline (this is not possible with a variator).
From the above, we conclude that a robotic gearbox is still far from the comfort of an automatic machine. Moving on to the positive aspects of robotic transmission:
- Low cost in comparison with the same automatic or CVT.
- Economical fuel consumption (here the mechanics are even inferior, but the variator is better in this regard: smooth and stepless shifting saves more fuel).
- Rigid connection of the engine with the driving wheels, due to which it is possible to take the car out of a skid or to brake with the engine using gas.
Robot with two clutches
Due to the numerous disadvantages inherent in a robotic gearbox, the developers decided to go further and still implement the idea of creating a gearbox that would combine all the advantages of an automatic machine and mechanics.
This is how the dual-clutch robot developed by Volkswagen was born. He received the name DSG (Direct Shift Gearbox), which translated from English means “gearbox with synchronized shift”. Preselective transmission is another name for the second generation of robots.
The box is equipped with two clutch discs: one includes even gears, the other - odd ones. Both programs are always on. While the vehicle is moving, one clutch disc is always ready, and the other is in a closed state. The first will engage its transmission as soon as the second is disengaged. As a result, gear changes are almost instantaneous, and the smooth operation is comparable to that of a variator.
The dual clutch box has the following characteristics:
- it is more economical than a machine;
- more comfortable than a simple robotic box;
- transmits more torque than a variator;
- provides the same rigid connection between the wheels and the engine as the mechanics.
On the other hand, the cost of this box will be higher than the cost of mechanics, and the consumption is higher than that of the robot. From the point of view of comfort, the CVT and the automatic still win.
Draw conclusions
What are the differences between a variator and a robot, and which of these gearboxes is still better? The variator is a kind of automatic transmission, and the robot is nevertheless closer to the mechanics. It is on this basis that it is worth making a choice in favor of a particular gearbox.
Transmission preferences usually come from the driver himself and are based on his requirements for the car, as well as his driving style. Are you looking for comfortable driving conditions? Then choose a variator. Do you prioritize reliability and ability to ride in difficult road conditions? Your choice is definitely a robot.
Choosing a car, the driver must personally "test" both variants of boxes. It should be remembered that both the robot and the variator have their own advantages and disadvantages. The purpose for which it is planned to use the car will also help to determine the choice. In a calm urban rhythm, a variator will be preferable to a robot that simply will not “survive” in endless traffic jams. Outside the city, in difficult road conditions, when driving at high speeds or when driving sports, a robot is preferable.
Questions and answers:
What is better variator or classic automatic machine? This is not for everybody. The fact is that the variator provides smooth stepless gear shifting (more precisely, there is only one speed in it, but the gear ratio changes smoothly), and the automatic machine operates in a stepped mode.
What's wrong with a variator on a car? Such a box does not tolerate a large torque, as well as a sharp and monotonous load. Also, the weight of the machine is of great importance - the higher it is, the greater the load.
How to determine what is a variator or automatic machine? All you need to do is drive a car. The variator will smoothly pick up speed, and light jolts will be felt in the machine. If the machine is faulty, the transition between speeds will be more distinct.
