CVT transmission - advantages and disadvantages of a gearbox and a variator in a car

The CVT transmission has various trade names, such as Multitronic for the Audi brand. Unlike traditional automatic solutions, the number of gears here is - theoretically - infinite, therefore, there are no intermediate steps (there is a minimum and maximum). Learn more about CVT transmissions!

How does a variator work? What makes it stand out?

Thanks to a specially designed CVT transmission, the power of the vehicle's power unit is optimally used. This is due to the fact that it automatically selects the gear ratio so as to maintain the engine speed at the appropriate level. During normal driving this may be 2000 rpm, but when accelerating it may rise to a level where the engine reaches its maximum torque. It is worth noting that the mechanism is excellent for both gasoline and diesel fuel, and even in hybrid cars.

Design and operation of CVT continuously variable transmission

One of the main elements on which the design and operation of every modern CVT transmission is based is a pair of bevel gears (output and clutch), called the CVT. The complex structure also consists of a drive transmission mechanism through a heavy duty steel belt. It is a chain of several hundred links. They are specially selected for thickness, width and even taper angle. However, innovative technological solutions could not function normally without the participation of electronics.

The central element that selects the parameters with which the car's stepless variator works is a special automatic transmission control unit. It checks the position of the accelerator pedal as well as the vehicle speed and the constant speed of the drive unit. On this basis, it controls the movement of the variator by moving the bevel wheels closer or further apart. Thus, it changes their working diameter and therefore changes the gear ratio currently used. The mechanism works similarly to a bicycle derailleur, but in this case, we do not have the restrictions of intermediate gears in the form of gears.

The use of continuously variable transmissions in modern cars.

Due to the specifics of the operation of the variator, Automatic transmission continuously variable transmission is mainly used in modern cars with small dimensions and, accordingly, low curb weight. As a rule, they have motors with low power and low maximum torque. Due to this, the belts or chains that transmit the drive are not subjected to excessive loads, which allows you to create highly reliable transmission mechanisms. Cars equipped with engine systems with a torque of about 200 Nm are considered optimal here.

CVT transmission in 4×4 vehicles

Innovative CVT transmissions are also found in large 4×4 vehicles, as exemplified by the models produced by the Japanese Mitsubishi brand. Skilled engineers have designed them to the point where they are ideal for vehicles that are comparable in size to larger vehicles or trucks. Solutions of this class are also used in two-wheeled vehicles, for example. motorcycles. The first scooter equipped with this type of gearbox appeared on the market as early as 1938. 

Benefits of CVT

One of the biggest benefits of a CVT transmission is the ability to reduce fuel consumption. You will see savings, especially if you follow the rules of economical driving and anticipate the situation on the road. Of course, more dynamic use of the accelerator pedal will definitely affect fuel consumption, regardless of whether the car has an automatic or manual transmission. Another advantage is the ability to reduce operating costs in vehicles equipped with high torque engines, i.e. in diesels.

An oft-cited benefit that you will definitely notice when driving around town is the smooth ride and quick back and forth changes in direction. 

Disadvantages of a variator box 

The disadvantages include a slightly louder operation of the stepless variator compared to a conventional machine. This is also due to the noise coming from the engine compartment, created by the drive (although the speed of movement is approximately constant). Many drivers also pay attention to the frequency of gearbox failures, but most often it is not the result of the design itself, but of improper operation and maintenance.

The most common malfunctions of a variable speed automatic transmission (e-CVT)

One of the most common faults in CVT automatic transmissions is excessive drive belt (or chain) wear. The wheels that make up the CVT system, which is the most important element of the continuously variable transmission, are also subject to gradual wear.

The faster occurrence of failure is primarily affected by excessive use of the system, i.e. dynamic, sporty driving or hard acceleration. For this reason, a car with a CVT transmission should not be used for track or street racing. It is also important to change the gear oil regularly, as the recycled lubricant increases the friction forces inside the automatic transmission, and, consequently, its faster wear. It is worth noting that many of the problems have been eliminated in the latest mechanisms marked e-CVT used in hybrid vehicles.

The cost of operation and repair of the variator

High operating costs and ремонт Variable speed gearboxes are one of the most common arguments against this type of decision. Should you accept their argument? Not necessarily, because most often problems arise due to improper operation of the transmission unit, and at the same time maintenance of the car by unverified mechanics. The result of this procedure is expensive services, which are also associated with a significant price of spare parts.

Be aware that these CVTs are usually slightly less durable than the conventional automatic transmissions used in modern designs. Self-propelled guns private. However, they provide a smoother ride and acceleration, and at the same time are characterized by much lower fuel consumption while maintaining the principles of "eco driving". Their obligatory part is a special electronic controller, which can fail due to moisture entering the system or power surges associated with connecting a rectifier to charge the battery.

Practical and functional CVT gearbox

Recommended by many experienced mechanics and garage owners, the practical and functional CVT transmission is an excellent choice for many people. Its advantages will be especially appreciated by users of vehicles, mainly moving around the city. With proper maintenance, the continuously variable automatic transmission has a long service life and trouble-free operation.