Many drivers believe that transmissions are divided into two groups: manual and automatic. In some ways, this is true, but the automatic transmission is classic, which everyone is used to calling “automatic” (automatic transmission), and a variator (CVT). Both of these gearbox options are now firmly established in the mass segment. automotive market. But at the same time, there are many rumors, some of which are true, about reliability, economy, speed characteristics each of them. In the framework of this article, we will consider what really are the pros and cons of the variator and the machine, and how they differ from each other.
Please note: Within the framework of this article, it is the automatic transmission and the variator that are considered. There is still a so-called “robot” on the market - this is another group of automatic transmissions. IN percentage the variator and the robot are installed on about 25% of cars with automatic transmission in this moment, and a full-fledged machine for the remaining 50%.
Automatic transmission
The standard automatic transmission is used on mass cars much longer than the variator, which is why there is a myth about its greater reliability.
The design of such a gearbox may vary slightly, depending on the manufacturer, but, in general, it is arranged as follows. Torque from the engine is transmitted through a torque converter. The work takes place under pressure, that is, there is no rigid engagement between the units. You might think that due to the lack of a rigid engagement, there is nothing to break, but this is not so. The design of the automatic transmission contains shafts with planetary gear And steel discs with friction clutches, when compressed and unclenched, gears are switched, that is, the necessary couplings are connected. Two more important element in the design of the machine, it is a hydraulic unit and a high-pressure pump.
Because of what the automatic transmission breaks
Having considered the design of the automatic transmission in a simplified way, one can understand that in fact the design of an automatic transmission is quite simple. Most often, the cause of its breakdown is improper maintenance. Drivers often do not change the oil in the automatic transmission, which leads to serious problems.
During the operation of the gearbox, the oil in it gradually loses its properties and a lot of debris appears in it. This leads to the fact that the elements of the gearbox are clogged - filters, valve body, radiator, and so on. Eventually, oil filter can't work normally and create required pressure, which leads to the scrolling of the clutches on the metal discs. The driver feels this problem as jolts when shifting the gearbox, or the gearbox stops turning on the necessary gears altogether.
The above problems in the gearbox can lead to even more trouble, up to physical damage to the planetary gears and wear. friction lining torque converter.
Please note: When purchasing a used car with an automatic transmission, make sure that the automatic transmission oil does not have a burning smell. If such a smell is present, this clearly indicates the presence of burnouts in the friction clutches and their high wear. A gearbox with such defects will not work for a long time.
What resource does the machine have
Drivers who are accustomed to driving a mechanic often say that they do not switch to automatic because of their short service life. Such an opinion has been automatic boxes gears for a long time, despite the fact that many automakers produce extremely reliable automatic transmissions.
For example, many Japanese cars manufactured in the late 80s and 90s, automatic transmissions are still driven by native automatics, on which minimal work has been carried out, while their mileage already exceeds 500 thousand kilometers.
In fact, the resource of the machine directly depends on its maintenance. Despite the fact that in the books on technical operation A car does not always indicate the need to change the oil in the automatic transmission; this must be done every 50-70 thousand kilometers. Along with changing the oil in the machine, it is imperative to change the oil filter and clean the radiator. Ideally, when performing such work, also remove chips and other waste products accumulated at the bottom of the machine body.
Pros and cons of the machine
Let's highlight the obvious advantages of an automatic transmission:
Note the disadvantages of the machine:
- Low dynamics. The car will accelerate slower on the machine than on a manual gearbox (with skillful use) or on a variator;
- Gear availability. Despite the smooth operation, the driver may feel some jolts when shifting gears. CVTs do not have this problem, as there is virtually no gear change;
- Efficiency costs for work. Since the work takes place with the help of a torque converter under oil pressure, while there is no direct connection between the transmission and the engine, part of the efficiency is wasted. This results in higher fuel consumption on vehicles with automatic transmission.
As you can see, the automatic transmission is reliable, but has less than ideal power characteristics. Whereas the variator can be considered its opposite.
Variable speed drive
Such gearboxes began to be installed on a car in the middle of the 20th century, but they did not immediately gain mass. But they were remembered when boxes were needed that have a lower efficiency consumption than a conventional automatic machine, and at the same time do not require the driver to make any effort when shifting gears.
The variator is called stepless. As you can understand, unlike the machine, such a transmission does not have the usual speeds. The design of the box implies the presence of a driving and driven pulley, which are parallel to each other. They are connected to each other by a metal belt in the shape of a trapezoid. The variator cones have sliding halves. At the moment when the drive pulley is moved apart, the belt rotates along a small diameter, this can be considered an analogue high gear on the machine. When the pulley is moved, the belt rotates over a large diameter, thereby obtaining the maximum gear ratio, that is, the first transmission.
Depending on the smooth movement of the pulley, the gear ratio changes. This leads to an increase / decrease in speed, although there are no such speeds, as in an automatic machine, in the variator. Since the transfer of torque from the engine to the transmission and wheels is rigid, it is possible to maximize the efficiency transfer.
Why does the variator break?
As in the case of the machine, improper maintenance leads to the failure of the variator. Such gearboxes are even more demanding on oil than automatic transmissions. An oil change in the variator is also carried out every 50-70 thousand kilometers, and this is a must here. If you do not change the oil in the variator in time, then:
- The oil pump will become clogged, due to which it will not be able to create sufficient pressure;
- The belt will begin to slip, because the shafts will not be able to compress and decompress it sufficiently;
- This will lead to increased wear belt and break, which will cause damage to other components of the variator.
It is also worth noting that there are much more electronic components in the variator than in a conventional machine. As a result, they are more likely to fail.
What is the resource of the variator
Unlike a conventional machine, the variator has a shorter service life. Even if you follow him and change the oil in a timely manner, he will be able to cover about 120-150 thousand kilometers, after which the belt breaks, and this will lead to serious damage other components of the box. To prevent this from happening, it is recommended to replace the variator belt at 120-150 thousand kilometers.
As you can understand, the driver of a car with a CVT must know that it is necessary to carry out timely diagnostic and repair work with the box, otherwise it will lead to the need for it overhaul or replacement. Most often, drivers do not think about this, not distinguishing a CVT from an automatic, and this leads to serious problems.
Pros and cons of the variator
The advantages of variators include:
- Increased efficiency. For CVTs, the efficiency is approximately 5-10% higher than for automatic machines. This also affects fuel consumption, which is less on cars with CVTs;
- Smooth running. The absence of gears leads to smooth operation of the gearbox;
- Fast acceleration. Due to the lack of the need to shift gears, acceleration on a car with a CVT is smoother;
- Easy control. As in the case of a machine gun, in the CVT, the driver just needs to select the desired mode of operation for the car to go.
The automatic transmission is found in three types: robotic gearbox, classic machine and variator. When purchasing a car, you should be aware of the advantages and disadvantages of each type. Robotic ones are rare so far, so consider the two remaining types. What is better - an automatic or a variator, which box should be preferred? Let's figure it out.
What is "automatic" on a car
The automatic transmission (automatic transmission) was invented to make life easier for the driver. At his disposal are two pedals - “gas” and “brake”, as well as a selector handle, switching which, the owner of the car selects the automatic transmission mode. The machine changes gears and provides movement independently.
Automatic transmission design
Automatic transmission in the usual version is a torque converter. It was invented at the beginning of the last century. The modern classic machine consists of
What is a variator
The second most popular gearbox is a CVT gearbox. The modern name of the variator is CVT (Continuously Variable Transmission), with in English translates as "continuous torque transmission". Invented the principle of infinitely variable torque transmission by Leonardo da Vinci. The first simple variator was used in mills, later used in the construction of machine tools for processing metal and wood.
CVT cars began to be installed in the middle of the last century. Hubert van Doorn, an engineer originally from Holland, thought of this. The first automobile stepless gearbox was called Variomatic and was installed on DAF cars in the 50s of the 19th century.
Movement design
Structurally, the stepless switching box consists of two cones that move relative to each other and are directed towards each other. They are connected by a belt or chain. As the cones move, the gear ratio changes. Modern CVTs more complicated, but the principle of action is exactly the same.
On the photo CVT Toyota Rav 4
Which is better: "automatic" or "variator"
Due to different design features the behavior of a car with an automatic and a variator is different. Cars with CVT do not have a "dip" in traction during acceleration. Speed and power increase or decrease gradually.
The machine, on the other hand, spends some time switching gears, so there are periods when the torque is not transmitted to the wheels, therefore, when accelerating, a car with an automatic transmission “twitches”. Engineers are constantly trying to reduce the switching time between stages. IN modern machines it is almost impossible to notice the loss of traction. The twitching appears only during aggressive, high-speed driving.
A little about economy and reliability
Which of them is more profitable and reliable? Let's compare some key indicators:
- Fuel consumption: a car with an "automatic" is gluttonous by 10-15%.
- The CVT design is lighter and takes up less space in the car body. Because of this, the interior of such a car can be more spacious and comfortable.
- Transmission fluid: CVT requires more frequent replacement oil, and the cost of CVT fluid is higher.
- Repair: an automatic transmission is cheaper to operate and repair. Structurally, the variator is much more complicated, so its repair can significantly hit the pocket of the car owner.
- Reliability: the variator does not withstand a large load, it is more “gentle”. Its belt drive will quickly fail when towing, off-road driving, sports riding. "Automatic" is more reliable when operating in difficult conditions.
How to choose on popular car models
Despite the obvious advantages and disadvantages of both options, you need to choose the right one based on the brand. Every car has its problems and weak spots, so I have highlighted the most popular choice questions below.
CVT for Nissan Qashqai
Nissan Qashqai since 2014 began to be equipped with CVT
Since 2014, CVTs from Japanese manufacturer Jatco (Jatko). Claimed guarantee period 120 thousand km. According to the owners, the actual service life is from 130 to 200 thousand km.
The variator on the Nissan Qashqai is not able to withstand heavy loads. Therefore, such a car should not be towed, pulled a trailer, and even more so drive off-road. The service life of the variator is reduced by 1.5–2 times. This is an ordinary city car, not an SUV.
When operating a Nissan Qashqai with a CVT, one should not forget about replacing transmission fluid and the filter element inside every 60–70 thousand km, and the outer cartridge should be changed every 30–40 thousand km.
The most common breakdown of the Nissan CVT transmission is the failure of the microswitch - the “limit switch” on the handle, as a result, it is impossible to switch from the “Parking” position. Repairs are inexpensive and replacements are quick.
CVT in Subaru XV
Subaru XV has been restyled
Subaru XV is available with CVT and manual. The stepless shift box has Subaru name Lineartronic CVT. Engineers Japanese concern long ago they abandoned the installation of an “automatic machine” on this model due to the high cost and bulkiness.
Lineartronic variator allows efficient use of traction capabilities power unit, save fuel. It provides smooth running and high ride comfort. Lineartronic is highly sensitive, cheerfully responding to changes in the position of the accelerator pedal and engine speed. Another advantage is compactness: as a result, there is more space in the cabin.
CVT in Subaru XV - reliable unit, and it is difficult to find negative feedback from the owners about his work. One of the issues to be considered is unstable work engine at hard braking. If the car stalls when the brake pedal is pressed sharply, then it is necessary to change the transmission fluid in the variator as soon as possible.
In case of untimely actions, the repair of the box will cost much more!
According to the manufacturer, when operating a car in difficult conditions, an oil change in the gearbox should be carried out every 30-40 thousand km. The conditions on our roads can be safely attributed to difficult, therefore, to extend the life of the variator and the car as a whole, follow the manufacturer's recommendations.
Renault Captur: automatic or CVT, which is better?
One of the popular colors of Renault Kaptur in 2018 is orange "Arizona"
The French car manufacturer offers its fans complete sets with mechanics, automatic and CVT. Automatic transmission goes to 2-liter, CVTs are installed on Renault Captur 1.6 liters. Four-wheel drive only comes with manual or automatic.
The variator is produced by Jatco, unification was carried out for Renault. Engineers have implemented personal settings in the stepless gearbox operation algorithm.
The automatic transmission is installed the penultimate generation, a new version the unit simply does not fit into the body, and the cost of a new generation automatic transmission is high. The manufacturer wants their car to be more affordable in terms of price, so do not rush to install a new machine.
If you make a choice: automatic or CVT, then the main criteria can be the cost of maintenance, efficiency and operating conditions. For a quiet city ride, a CVT is suitable, for lovers of sports driving and off-road best solution Will it be manual or automatic.
How to choose a gearbox for Toyota Rav 4
On Toyota RAV 4 choose automatic more often
Toyota RAV4 lovers living in the metropolis prefer automatic transmissions. They are more reliable and cheaper to repair, but they have several drawbacks: fuel consumption is 10–15% higher, equipment with automatic transmission is more expensive, cars with it are less dynamic.
CVT in Toyota Rav 4 supports optimal speed engine, which saves fuel and allows you to get stable dynamics during acceleration. The movement of the car is smooth and comfortable. Resource good work continuously variable box, according to the manufacturer, up to 100 thousand km. The machine will last without problems up to 150 thousand km.
When choosing between a CVT and an automatic, you should decide what is more important for the owner: efficiency or reliability. The second most important criterion is driving style. For a quiet movement around the city, a variator is more suitable.
Useful video about types of checkpoints
Autobuffers will protect the chassis in this harsh winter!Penalties for crossing the stop line and speeding will not bother you anymore!
comparison table
| Evaluation criterion | Machine | Variable speed drive |
| Warranty period (subject to the manufacturer's recommendations) | Up to 150,000 km | Up to 100,000 km |
| Package price | Expensive | Cheaper |
| Fuel consumption | Increases by 10-15% | Optimal |
| Maintenance (change of transmission fluid, filters), repair | Cheaper | Expensive |
| Dynamism | There is jerking when accelerating | Smooth stable acceleration, no dips |
| terms of Use |
CVT or automatic - which is better? Or maybe a robot or some kind of new generation automatic transmission, such as DSG? Every car enthusiast faces these questions when choosing a new car. Today, many modern cars are equipped with automatic transmissions, from trucks to minicars. In this article, we will look at the pros, cons and differences between the main types of automatic transmissions.
More and more car owners, buying new car, are moving from the traditional manual transmission on various kinds of automatic boxes. This is easily explained by the fact that using an automatic transmission is easier and more convenient. As for women, among them the number of adherents of "machine guns" is the majority, and overwhelming.
At the end of this article, watch a video review of popular types of automatic transmissions, with a description of their main advantages and disadvantages.
It should also be borne in mind that when buying a car for secondary market, a person far from automotive technology can easily fall for the bait of unscrupulous sellers who pass off a robot or a variator as a classic machine. Therefore, it is desirable for each driver to be able to distinguish these types of gearboxes from each other.
Types of automatic transmission: torque converter, variator, robot
The following devices are most often referred to as automatic gearboxes (abbreviated as gearboxes):
- Torque converter (classic automatic);
- Variator (CVT);
- Robotic gearbox (robot).
Each of them has its own differences, pros and cons. So before identifying the winner, you should consider them all in turn in more detail.
Torque converter (classic automatic transmission)
Torque converters are so widespread that it is this type of automatic transmission that has become a household name for all other types of automatic transmission - "automatic gearbox".
A characteristic feature of the torque converter is the presence in it of a special transmission oil, which constantly circulates in a vicious circle, being under pressure. It is the flow of oil that transmits torque from the engine to the wheels of the car.
Automatic boxes are constantly being upgraded, and if ten years ago a 4-speed automatic was considered the norm, now it is already an obvious anachronism, and automatic machines with 6, 7 or even 8 gears have taken its place.
The following can be distinguished pros classic machines:
- Ease of use;
- Availability manual mode switching;
- The inability to overheat the engine.
But also minuses The machines also have:
- The high cost of a car with automatic transmission;
- Expensive maintenance and repair;
- The impossibility of long-term towing;
- High fuel consumption.
Nevertheless, designers are successfully working on eliminating all these shortcomings, and will soon be able to rid the machines of them.
Variator (CVT)
A CVT is a type of continuously variable transmission. In abbreviated form, this type of gearbox is indicated by three Latin letters CVT, from the English Continuously Variable Transmission.
Distinguishing the variator selector from the shift lever of a conventional machine is sometimes difficult and experienced car owner. However, despite the external similarity, such boxes work in a completely different way.
Roughly speaking, the variator consists of two pulleys (discs), between which a belt is thrown (less often, a chain). The pulleys can move and move apart, due to which the gear ratio changes.
A distinctive feature of the variator is the complete absence of gears and, as a result, switching between them. Gear ratios change, but this process is continuous. Excellent smoothness - that's the main trump card of the variator. By by and large, acceleration on a car with a variator is somewhat similar to the acceleration of a trolleybus. So the comfort of the driver and passengers will be ensured.
Because the CVT doesn't have to "click" gears, the transmission is constantly at its peak of torque, hence the car accelerates faster.
And so, the variator can record the following as an asset: pros:
- Low fuel consumption;
- Fast and extremely smooth acceleration;
- Comfort;
- Minor weight.
But the widespread introduction of CVTs is also hindered by its minuses:
- It works quite noisy, which is felt in the cabin;
- Less service life than classic automatic transmissions;
- High cost of repair and maintenance;
- Dislikes abrupt starts and aggressive driving;
- High price.
Robot (robotic gearbox)
Robotic gearboxes are a compromise between automatic and manual transmission.
In fact, the robot is the same “mechanics”, only the control unit, controlled by servos, is engaged in gear shifting. When switching gears by the robot, the same pause occurs as in cars with mechanical box.
In addition to the pause between shifts, drivers have to put up with some other shortcomings of robotic transmissions. Main minuses robot are expressed as follows:
- Shocks and jerks when switching;
- "Thoughtfulness" of the robot;
- The obligation to constantly turn on the "N" (neutral) mode in traffic jams, in order to avoid overheating of the clutch;
- Impossibility of towing.
So this box has enough shortcomings, but cars with it continue to be sold, because these disadvantages somewhat level out such pros robots:
- Low cost (much cheaper than "automatic" or CVT);
- More low consumption fuel.
Despite this, such robots are already clearly becoming obsolete and are giving way to other developments, such as, for example, the preselective transmission of the DSG type.
DSG gearbox - what is it?
DSG ( Direct Shift Gearbox - Synchronized Shift Transmission) is an evolutionary continuation of robotic checkpoints. It is also called a preselective transmission - this is the second generation of "robots".
Such boxes are by far the most advanced. They are equipped with two clutch discs at once - one switches even gears, and the second - odd ones. In fact, these are two gearboxes in one housing.
Zest DSG boxes consists in the fact that two gears are constantly included in it: during movement, only one of the 2 clutch discs is closed, and the second is in constant readiness, and turns on its gear as soon as the first disc opens. Thanks to this scheme, switching occurs almost instantly, and the smoothness of operation is comparable to the variator.
But even such a seemingly ideal gearbox as a DSG has its drawbacks. The design of preselective transmissions is extremely complex. All this leads to the fact that its service can not be called cheap.
In addition, even large service stations often do not undertake to repair DSG boxes. And their repair, in most cases, is simply impossible. Therefore, in the event of a breakdown, it is often necessary to change the entire preselective transmission assembly, and only sometimes it is possible to confine ourselves to replacing electronic block management.
Also in the list of disadvantages of boxes DSG gear overheating of the clutches after a long drive can also be brought in, as a result of which, over time, jolts appear when switching.
Considering all of the above, we believe that preselective transmissions, despite all their manufacturability, are still quite "raw", too expensive and unrepairable.
After we have studied the strengths and weak sides automatic transmissions, we can return to the consideration of the question of which is better - a CVT or an automatic? But there is no definite answer to it.
Proponents of automata rely on enough high reliability such boxes, their convenience, availability different modes operation and the possibility of independent switching. They blame CVTs for noise in the cabin, low resource and periodic overheating, which directly leads to costly repairs, or even replacement of the gearbox.
On the other hand, supporters of the variator directly say that after driving a car with such a box, even the smoothest automatic machines seem "twitchy". In addition, CVTs have lower fuel consumption. As for the higher cost of repairs and frequent breakdowns, then many continue to turn a blind eye to these aspects.
Nevertheless, it seems to us that in this struggle, preference should be given to classic automatic box(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, far outweigh all their advantages.
If you soberly assess the situation, it becomes clear that today, among all types of automatic transmissions, the design of the torque converter is the most mature and reliable, and many of its shortcomings have either already been eliminated or are not critical.
Video: robot, automatic or CVT - which is better?
In order to determine how the variator differs from the machine, you must first figure out what an automatic transmission and a variator are.
Automatic checkpoint.
The automatic machine appeared in shipbuilding in 1903. This invention is attributed to the discovery of the German professor Fettinger, who proposed the use of a hydrodynamic transmission to untie the ship's propeller and engine. From this came the fluid coupling - one of the main parts of the automatic gearbox.
In 1940, the Hydramatuc automatic transmission was first used in America. These machines are still in use today.
Automatic transmission consists of 2 main elements - a gearbox and a torque converter, we read the post. The latter replaces the clutch and ensures smooth shifting. The reducer drives pairs of gears in a state of constant engagement, which results in one complete mechanism with several steps at the same time. Now they use 4-, 5- and 6-speed automatic transmissions.
The disadvantage of such a transmission is the lack of dynamic gear shifting. By the way, it is written about how to use an automatic transmission.
Variable gearbox.
The CVT is a type of automatic transmission, only without fixed gear shifts. These transmissions are used in automotive manufacturing recently, but the variator was invented back in 1490 by Leonard Da Vinci. It consists of two cones directed towards different sides with a stretched belt between them, about the principle of operation of the variator. Such primitive variators were used in mills, then on machine tools, and they began to be used in cars only in 1958.
Hubert van Doorn invented stepless box gear shift called CVT. The design of the variator in our time is much more complicated. main feature is that it smoothly distributes traction to the engine and wheels.
How to distinguish a variator from an automatic?
Although the variator is a kind automatic transmission, but there are differences. The main feature of the variator is the absence of fixed gears. During downshifting or upshifting, the CVT constantly changes the gear ratio, while switching is smooth and imperceptible. Thus, the variator ensures a smooth start of the car, i.e. no jerking when changing gear. Also, cars with CVT are distinguished by ergonomics together with high dynamics. Another difference can be called the fact that the variator has an infinite number of gears that provide the car engine with the most profitable operation, regardless of the speed and driving speed.
So, let's summarize how the variator differs from the machine:
- acceleration dynamics and low fuel consumption;
- "Jerk-free" gear shifting;
- more expensive and difficult repair, which not every service station will undertake, unlike an automatic machine that has already been well studied, its repair will be cheaper;
- the need for a certain usually expensive oil for the variator, which is sometimes difficult to find in stores;
- a car with a classic automatic will lose in acceleration to a car with a variator, but when driving, the variator will show a higher and more stable speed, since it does not waste time shifting gears and keeps the engine in maximum operating mode.
Whatever transmission you choose, automatic or CVT, you will have the advantages of an automatic transmission:
- high level of driving comfort due to the absence of constant gear changes;
- the machine reduces the load on the car engine and its undercarriage which prolongs their service life;
- ensuring a smooth ride and the absence of jerks when downshifting or upshifting.
But the disadvantage of the machine can be called increased consumption fuel and more expensive repairs and maintenance compared to mechanics.
Modern cars equipped with several types of transmissions. domestic cars until recently, they were mainly equipped with a manual gearbox. Russian motorists got acquainted with the automatic transmission after they began to import cars from abroad into the country. But so far, few people have come across a variator. The widespread use of this type of transmission is just beginning.
This is how the variator works
The principle of operation of the variator
The variator was invented a long time ago. A description of the basic principles of his work is found in the notes of Leonardo da Vinci, dated to the end of the fifteenth century. The first cars with a CVT appeared in the fifties of the last century. These were DAF subcompacts. Then this transmission began to equip some Volvo models. But the variator was not widely used at that time. And only in our days, developers have again begun to develop and actively introduce this type of transmission into production.
The principle of operation of a variator or CVT (an abbreviation for English continuously variable transmission) is fundamentally different from classical mechanics and automatic transmission. It does not have a fixed gear shift. Switching speeds from first to second, etc. absent. The gear ratio from the engine shaft to the wheel drive changes smoothly as the vehicle accelerates or decelerates. Modern cars are equipped with toroidal, chain and V-belt variators. The last type of transmission is the most common.
Consider the principle of operation of the variator with V-belt transmission
The shift of the tapered halves of the pulley leads to the pushing of the belt to the outer diameter, and the extension to the movement towards the axis
The basis of the V-belt variator is two pulleys. Each pulley consists of a pair of cones facing each other. Sliding and expanding the cones allows you to change the diameter of the pulley. The pulleys are connected by a V-belt. The shift of the tapered halves of the pulley leads to the extrusion of the belt to the outer diameter, and the extension to the movement towards the axis. Thus, the radius along which the belt runs smoothly changes - from smaller to larger and vice versa. Accordingly, it changes gear ratio engine - drive. If the driving and driven pulleys are in an intermediate position (pulley diameters are equal), the transmission becomes direct - the engine shaft speed is equal to the drive speed.
To start the car, a conventional clutch or torque converter is provided, which is blocked after the start of movement. The pulley disks are controlled electronic system, consisting of a servo drive, sensors and a control unit.
An important role in the operation of this transmission is played by such a detail as the variator belt. Obviously, the usual rubberized belt, of those used in the drives of an air conditioner or generator, will not work here. It will not withstand the loads arising from the transmission of torque in the variator, and will quickly wear out. Therefore, the variator V-belt has a rather complex structure. This may be a steel tape with a special coating or a set of cables, on which many trapezoidal steel plates are strung.
Belt variator
In cars brand Audi install variators with a belt made in the form of a wide steel chain. Used to lubricate the chain special liquid. With strong pressure at the points of contact of the chain with the pulley, it changes its state. This allows the chain to transmit high forces without slippage.
Variator - pros and cons
The advantages of a car with a CVT include smooth and at the same time quite fast acceleration. Comfortable ride on the variator is comparable to driving on - the car also has only two pedals and there is no need to manipulate the gearshift lever. This is especially true for novice drivers. The engine with a CVT transmission will not stop at a traffic light and will not allow the car to reverse on a steep slope.
Thanks to the variator, the load on the drive and engine elements is distributed evenly in any driving style. The engine with a variator always runs smoothly, in a favorable sparing mode. This greatly increases its resource, reduces fuel consumption, and reduces the emission of harmful substances into the atmosphere.
Disadvantages of the variator:
- The high cost of transmission fluid and the inability to replace it with conventional oil
- The high cost of repairs and the lack of narrow-profile qualified specialists
- The need to take readings from a large number of different sensors. If even one of them fails, serious violations are observed in the operation of the entire transmission.
- Impossibility of installation on cars with a powerful engine
Although it is worth noting that with regard to equipping with a CVT transmission, more powerful engines there is some progress. For example, on the Audi A4 2.0 TFSI (engine power 200 hp), the variator with the multitronic chain works successfully. A Nissan crossover Murano with an engine capacity of 3.5 liters and a power of 234 hp. equipped with an X-Tronic V-belt variator. If the variator is still unacceptable for trucks, then for cars it is a good alternative to mechanics or automatic.
In this video detailed overview automatic transmissions
Which is better - CVT or automatic
Many motorists ask themselves the question - what better variator or automatic? Short description the principle of operation of the variator was given above. Therefore, the difference between a variator and an automatic is quite clear. But is such a transmission better than automatic transmission - there is no definite answer. Everything is clear with the advantages of a variator compared to an automatic. This dynamic acceleration, and low fuel consumption, and greater resource engine. But here, as for, here the automatic transmission is still a winner. Although it cannot be said that automatic transmission repair is cheap, nevertheless, it will cost less than similar works with variator. And there are much more services that provide automatic transmission repair services.
CVT or mechanics which is better
The same question may arise with regard to manual transmission - CVT or mechanics, which is better? In terms of the advantages of the variator, the situation here is the same as with the machine. In terms of repair and maintenance, a mechanic is definitely cheaper than both a variator and an automatic. It would not be superfluous to note that the variator, as well as the automatic machine, are intended rather for lovers of calm, safe movement. Those who treat the car, first of all, as a means of quickly moving from point A to point B. For those drivers who simply love cars and everything connected with them, who like to feel one with their iron horse, I like to squeeze into the seat under the influence of the load from acceleration, I like to hear the roar of the engine - the answer to the question of the variator or mechanics which is better will be unambiguous - manual transmission.
Something else useful for you:
Tips for buying and maintaining a car with a CVT
In connection with expensive service and repair of cars equipped with a CVT, when buying, it is recommended to give preference to new cars with a guarantee. In the case of used cars, it is difficult to judge the degree of wear of the transmission elements. Repair of a faulty box may require additional costs, so much so that the total amount spent on the purchase and repair of a used car will be commensurate with the purchase of a new one.
Motorists, however, who decide to purchase with a CVT, should know how to check the CVT when buying. The easiest test is to warm up the car and move off. There should be no jerks at the start. If they are present, then, most likely, the resource of the transmission fluid has been exhausted. It needs to be changed. When changing the fluid, the filters are also changed. When checking the variator in all modes of operation of the transmission, there should be no extraneous noise.
When buying a car, the question may arise, what exactly is a CVT or, maybe, a classic automatic machine being sold to us? How to determine the automatic or CVT is under the hood? The fact is that it is quite difficult to visually determine the type of transmission. Even the designations of the switch modes for the machine and the variator are the same - P, R, N, D.
You can define a variator or automaton as follows:
- Carefully read the documentation for the car - the machine is denoted by the letters AT or A. CVT - CVT
- Collect information about specific brand car from directories, catalogs, on the Internet. Thus, you can find out what type of transmission is installed on the car brand of interest.
- Carry out a test drive. At dynamic acceleration the machine, shifting gears, gives tangible jolts. Simultaneously with the switching, the number of revolutions also changes, which can be determined by the tachometer or by ear. The variator accelerates without jerks when the tachometer needle is stationary.
- Some new CVT models do not have a dipstick to check the gearbox oil level. In automatic transmissions, an oil dipstick is always present.
Owners of cars with a CVT are recommended to visit every 24 thousand kilometers service station to check status working fluid. The oil in the variator is changed every 60 thousand kilometers. This is according to the manufacturer's instructions, but according to the recommendations of experts, it is better to change the fluid earlier after 30-40 thousand km.
How to ride a CVT
- At negative temperatures, it is not recommended to give a large load on the transmission immediately after the start of movement. Elements of the system should warm up at low speed.
- Try to avoid strong and abrupt loads, the CVT is not designed for racing, towing and off-road.
During operation, it is necessary to regularly check the condition of the wiring, connectors and sensors. When extraneous noise should be contacted immediately service center. Trying to repair the variator yourself, without skills and special tools, is not recommended.
