CVT Transmission: Definition, working & Application

CVT stands for continuously variable transmission, and this type of automatic transmission uses pulleys and a steel band instead of traditional fixed gears. It’s always automatically adjusting to your driving, and it provides smooth, step-less gear changes. Car manufacturers like CVT transmissions because they help improve fuel efficiency by containing RPMs, or engine speed.

What Is a CVT Transmission?

A CVT transmission, or continuously variable transmission, seamlessly changes through an unending range of effective gear ratios while you drive, whereas other kinds of mechanical transmissions offer a fixed number of gear ratios and have hard shifts between each.

CVT transmission systems are also known as single-speed, shiftless, and stepless transmissions. The shiftless nature of a CVT offers unparalleled flexibility that maintains constant angular velocity regardless of output speed. Additionally, a continuously variable transmission makes accelerating smooth and offers enhanced fuel economy.

CVT transmission stands for continuously variable transmission.

How Does a CVT Transmission work?

To see how a CVT works, you need to understand a manual and a traditional automatic Transmission. A manual has a set number of gears and the driver determines what gear ratio he needs. An automatic also has a set number of gears, but uses a hydraulic system that responds to the pressure created by the conditions to determine the gear required without operator input.

A CVT is similar to an automatic in that it doesn’t use any input from the driver, but that’s where the similarities end. A CVT has no gears. Instead, it has two pulleys. One pulley is connected to the engine and the other to the wheels. A flexible belt connects the two pulleys.

The width of the pulleys changes depending on how much power the vehicle needs. As one pulley gets bigger, the other gets smaller. Since neither the pulleys nor the belt is fixed, they can provide an infinite number of gear ratios in contrast to the automatic with a fixed number of gears.

Not all CVTs are created equal. The most common type is pulley-based, but some other types include toroidal CVT, which uses rotating pulleys along with power rollers to achieve the same result as the pulleys. The hydrostatic CVT uses pumps to control the flow of fluid, which then generates a rotary movement.

For more information about pulley check our article: What is pulley?

Why Do Automakers Use CVTs?

If CVT transmissions have been around for so long, why are they only now popular? Manufacturers are now finding that they tend to work well for their main customer base. A CVT gets as much power as possible from a smaller engine. This makes acceleration faster and more responsive, so the average driver has a better experience.

What Is Launch Gear?

Toyota recently made some changes to its CVT. CNET says it is now using what’s called a launch gearbox to give drivers the feel of a traditional gearbox. The starting gear is almost similar to the first gear of a normal automatic transmission.

When the vehicle speeds up, the transmission turns this off so it works as a CVT. Toyota says using these new fixed gear ratios doesn’t just feel more like a regular gearbox. It also increases belt efficiency and improves performance.

Which Is Better Between CVT and Automatic Transmission?

One of the advantages of a CVT is its ability to continuously change its gear ratio. This means that, regardless of the engine speed, maximum efficiency is always achieved. CVTs therefore often offer better fuel economy, especially when driving in the city.

According to Digital Trends, most cars equipped with CVTs offer a smoother ride than a similar car with a normal automatic. This is because the transmission never shifts. There are no abrupt downshifts when the car needs extra power, and there is no gear chase feeling that you sometimes get with a traditional automatic.

A CVT is lighter than a traditional automatic and this, combined with smoother operation, helps improve the fuel efficiency of vehicles equipped with a CVT.

The lack of a gearbox also makes it easier for CVT vehicles to find and maintain an ideal torque ratio. It is easier to take off from a traffic light and it is easier to climb difficult terrain as the variable gearbox allows it to run and stay in the correct “gear”.

For more information about automatic transmission check our article: What is an automatic transmission?

What Are the Pros and Cons of CVT Transmissions?

Advantages of CVT Over Automatic Transmissions

  • Outstanding fuel efficiency is a major advantage for your Bloomfield and Troy commutes. CVTs are always adjusting, so they keep engine RPMs low and consistent, avoiding the high engine speeds that suck down gasoline.
  • CVTs also have lower production costs because they have fewer moving parts than traditional automatics. This is another appealing factor to car manufacturers, and thus to car buyers as well.
  • CVTs deliver a smooth ride because the transmission doesn’t have to constantly switch gears.

Disadvantages of CVT Over Automatic Transmissions

  • You may feel a delay when you step on the accelerator. That’s because, compared to a regular automatic transmission, there’s a slight pause as the CVT band adjusts.
  • CVTs can be hard to get used to because they just don’t feel the same way a traditional automatic does. The engine sound is monotonous, and you don’t feel a connection with the car like you do when you can tell a gear has shifted.
  • In spite of the low initial costs of a CVT, repairs can be more expensive because the parts are more costly to replace. And because technicians need special training, it may be harder to find someone that can make the repair. This has become less of an issue as CVTs have become more common.

What to Watch Out for When Buying a Used Car With a CVT

You’ll need to do some extra research before you buy a used car with a CVT. Because of the expense of replacing a CVT, be sure you take a test drive, conduct an inspection, and check the warranty on it.

While test driving, look out for the following:

  • Slow shifting: While you don’t have to shift a CVT from first to second gear, you do have to shift between the park, drive, and reverse. If it takes more than a second or so for the transmission to shift, it can indicate a faulty CVT that may break down soon.
  • Strange sounds: CVTs are naturally louder than their traditional counterparts, but they shouldn’t be so loud that humming and whining are normal. If you hear excessive noise when accelerating, that’s a red flag.
  • Slipping: When you accelerate, you should experience a continuous, seamless acceleration. If it slips or momentarily loses power, the CVT is faulty.
  • Jerky shifting: Shifting should never jerk or jolt the vehicle.
  • Inconsistent rpm: A CVT should remain consistent, so if you notice a fluctuation in rpm while you’re driving at a steady speed, that may indicate a problem.
  • Dirty transmission fluid: If the transmission fluid is dirty, it could indicate an issue with the CVT, among other problems.