Continuously Variable Transmission (CVT): What Is It And How Does It Work?

CVT (Continuously Variable Transmission) Explained

The automotive landscape is an ever-evolving place, and the CVT transmission is among the latest advancements pushing progress forward. You'll find it in many new cars today, often with claims of excellent efficiency backing them. Those claims are true, and a CVT offers you many advantages for the daily drive. Naturally, there are downsides as well, but that's true of any transmission on the market. So, to decipher this modern advancement, we'll walk you through the ins and outs of a continuously variable transmission (CVT), along with the pros and cons one presents you with.

The CVT Transmission History

Where did it all begin? To be technical in the historical sense, the CVT transmission was conceptualized over 500 years ago by Mona Lisa painter and Renaissance inventor Leonardo Da Vinci. But that was solely a novel concept for a gear system; the first vehicular use occurred in the 1910s on a racing motorcycle. That still was a one-off use, and the CVT only saw true production starting in the late 1980s, with mainstream adoption coming in the early 2000s. It was still rare back then, but the CVT transmission finally became commonplace with the rise of efficiency-minded vehicles in the early 2010s.

You'll find a CVT used in many vehicle types, not just cars and SUVs. This includes everything from tractors and ATVs to motorcycles and airplanes. You'll also find them in many efficient and affordable used cars under $15,000 for sale.

Which Vehicles Use a CVT Gearbox?

While the CVT was limited to eco-oriented vehicles in the automotive world during its early years, you can find a CVT in everything from family SUVs to sporty sedans today. Have a glance at our used inventory, or new cars for sale, and you'll find many exciting vehicles using it. The CVT is still perhaps the best choice for internal-combustion efficiency, though, and it makes those eco-oriented choices even better.

So, that leads us to the inner workings of a CVT. Meaning of the initialism aside, a CVT, to put it simply, uses a belt drive to transmit the engine's power through the drivetrain and to the wheels. That's where the "continuously variable" part of the abbreviation comes into play. In essence, you have two pulleys, each with continuously variable diameters (can constantly be changed) connected by a belt or a chain. A shaft connects one pulley (drive pulley) to the engine's power output, and the other pulley (driven pulley) sends the power through another shaft and to the drivetrain.

As those pulley diameters vary, so does the speed and torque ratio for the power transmitted. Think about it like the gears on a bicycle. If your pedals connect to a large gear and send the power to a smaller gear, one rotation of the pedals can equal several wheel rotations - perfect for low-speed acceleration. Going from a small to large gear does the opposite. In essence, this is the concept behind both an automatic and CVT transmission. We'll get into the differences between them in a bit.

With a CVT transmission, those variable pulleys act like the gears of a bicycle, and the belt acts like the chain connecting them. When you get moving from a stop, the pulley diameters optimize accordingly to favor torque for acceleration. At high speeds, the ratio changes to select efficient and smooth horsepower delivery, in turn letting you cruise along efficiently and smoothly. That's the gist of it, but to understand it at a deeper level, let's look at how a CVT compares to an automatic transmission.

By a technicality, a CVT transmission is a type of automatic transmission, as no manual gear shifts are required. But, automatic transmissions in the traditional sense are something different entirely. While the ratios we discussed previously apply, physical gears are used to achieve the desired ratio rather than dynamic pulleys and a belt. Inside an automatic transmission lies a set of planetary gears, automatically meshing together using clutch packs to achieve an optimal gear ratio for the driving conditions at hand. Power is sent through these gears to an output shaft, in turn, powering the wheels.

A traditional automatic isn't the only type. An automated manual transmission (AMT) is another. Using the more straightforward manual transmission layout, an AMT automates the manual clutch in-and-out process, letting you focus on shifting gears. In theory, the CVT vs. AMT comparison is similar to CVT vs. a traditional automatic, as the gear-to-gear input-output function is the same. Another automatic transmission is a dual-clutch transmission (DCT), and it's more common to see today, mostly having replaced the AMT. The theory is similar, and both a DCT and AMT are performance-oriented transmissions.

So, in essence, an automatic transmission vs. CVT comparison revolves around fixed gear ratios for automatics and nearly infinite gear ratios on a CVT - but without needing additional parts to do so. What that means is you'll find far more mechanical complexities in an automatic. With that in mind, let's take a look at the various CVT pros and cons.

Starting things off, a CVT transmission is simpler in design. Drivetrain power loss is an inevitable force every car on the market faces, as turning the gears or pulleys inside a transmission is an act that itself requires power to perform. Said power is spent up before even hitting the wheels - on average, it's about 15% of total engine power. While other drivetrain components, including the driveshaft and differential, play their part in this, the inherent simplicity of a CVT transmission can cut down on the power lost.

That's also a part of the following advantage - greater fuel efficiency. While getting more power to the wheels help, those near-infinite gear ratios are the real culprit here. An automatic transmission usually will have between five to 10 gears. Each gear is designed for a specific scenario and limits just how adaptable the transmission is. That's not the case on CVT transmission cars, as optimal engine speed can be maintained at all times and in any driving situation for the greatest fuel efficiency possible. What's better than saving money at the pump? Not much.

Another factor of efficiency is that a CVT lets smaller engines shine because of the simpler design, less drivetrain power loss, and constantly optimized ratios. Four-cylinder engines achieve the best possible power output, and are made more efficient, more responsive, and quicker than what they're capable of with a traditional automatic. A CVT transmission is also smaller in layout, allowing designers to create more spacious interiors in a car.

Another great advantage is a smoother ride. There are no fixed gears to shift between, and varying the pulley ratio is a seamless process. As a result, the lurch or jerk associated with shifting gears is nowhere to be found. Better still, there's a delay in power as an automatic transmission finds the right gear and shifts to it; shifting on a CVT happens almost instantly. In a nutshell, with a CVT transmission, you're always in the perfect gear for both performance and efficiency.

Everything in life has its ups and downs; a CVT is no exception. The first of the CVT transmission problems involves subjective taste and habits. Driving a car with a CVT can feel off and rather strange if you're used to the feeling of a car with noticeable gear shifts. Certain characteristics like how a CVT can favor higher RPM while climbing a hill may also seem wrong, but don't worry; it's by design.

Driver preferences aside, another downside to a CVT is untapped potential. The automatic transmission became widely used after the end of the 1940s; the CVT only became commonplace in the past decade. While advancements are moving fast, the CVT transmission is still a relatively new, efficiency-oriented design. Simply put, if massive horsepower is a must-have for you, with efficiency being an afterthought, then your CVT options are next to none.

Another downside is also related to how new CVTs are. While comprehensive warranties like you'll find with our CPO cars for sale can combat it, there are fewer certified technicians who are trained on CVTs rather than automatics out there. That means an independent shop can charge more or not work on a CVT at all. Luckily, you have authorized service centers like ours to fill in.

But, a CVT also requires more frequent fluid changes than an automatic to avoid mechanical issues. It's not by a massive margin, but still something worth considering.

Experience CVT Smoothness Today

All in all, a CVT transmission has both benefits and downsides to consider. We're excited to see what advancements the future has in store for the CVT and just how smooth and efficient vehicles using it can get. To experience the supremely smooth feel of a CVT, our dealerships can offer you a test drive of current models equipped with one today.

Frequently Asked Questions:

Are CVT transmissions reliable?

In general, a CVT transmission is about the same as an automatic transmission when it comes to reliability. Of course, reliability also varies with driving habits, along with makes and models. That goes for automatic transmissions too. CVT transmissions also present the best blend of efficiency and reliability for smaller engines on compact vehicles. With fewer parts to present you with issues, a CVT transmission can provide you with years of reliable use.

Are CVT transmissions good?

Yes. A CVT transmission is good for many applications and aspects of driving. They provide maximum efficiency by constantly achieving the optimal ratios, greater performance with smaller engines, a smaller size that allows for roomier interiors, simpler construction with fewer parts to present issues, and seamlessly smooth driving.

Who makes the best CVT transmissions?

The maker of the "best" CVT transmission is a debate without an objective answer. That said, many consider Honda CVTs to be among the top offerings in the industry. That's because they're reliable, smooth, efficient, and very capable when used in vehicles like the CR-V. Overall, you can look to Honda when you want an excellent CVT transmission.

How long does a CVT transmission last?

A CVT transmission will last just as long as a traditional automatic when given the proper maintenance. Specifically, an average lifespan of over 100,000 miles can be expected for a CVT, with many drivers reporting that theirs has lasted for far longer.

What is CVT fluid?

Inside a CVT transmission, pulleys, a belt, and several other parts are constantly in motion as you drive. Lubrication is necessary, as, without it, friction would prevent proper function. CVT fluid provides that lubrication and keeps the transmission running smoothly.

Does CVT transmission fluid need to be changed?

Yes. Just like automatic transmission fluid (ATF), CVT fluid degrades over time and loses performance. Without changing it at the specified interval, things can go wrong over time and cause mechanical breakdowns. Refer to your owner's manual or recommended service interval to ensure that you change yours at the right time.

Holmes Auto Family - Frequently Asked Questions(FAQ)