• Continuously variable transmission provides a smooth  dri...
    Continuously variable transmission provides a smooth driving experience with seamless power delivery.
  • An internal view of the simple, lurch-prone AMT system.
    An internal view of the simple, lurch-prone AMT system.
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  • CVTs provide a smooth, premium and luxurious feel while d...
    CVTs provide a smooth, premium and luxurious feel while driving.
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Sponsored Feature: Nissan X-Tronic CVT automatic

5th Feb 2016 1:28 pm

We take a look at the transmission technology that offers the fun, comfort and practicality of an automatic With better fuel efficiency than a manual.

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It’s undeniable. Cars with automatic transmissions are steadily gaining popularity in India. And why not? Traffic conditions are bad and our roads aren’t getting any wider. Navigating the urban stop-and-go traffic is invariably a painful experience. Cars with automatic transmissions provide some much needed relief in these situations. They make driving a much more comfortable experience.

They were once considered a luxury. Understandable, since early automatics weren’t very efficient or economical. Buying one at those times in India could be considered a momentary lapse of reason. Today, thanks to advances in technology, the automatics available in the market are a far cry from what was available earlier. There are also a number of different types of automatic transmissions available in India today. There’s the traditional torque converter, the Automated Manual Transmission (AMT), the Dual-Clutch Transmission (DCT) and the Continuously Variable Transmission (CVT). Of these, the most popular and widely available in the market today are AMTs and CVTs. On the surface, both offer similar benefits - relatively inexpensive to buy, easy to drive and easy to live with. How then do you decide? And which one of these two is actually better? Short answer - CVT. Why? For that you’ll have to understand how it works. We’ll try not to get too technical with this.

How it works

An AMT is essentially a manual transmission with an automatic clutch and gear shifting mechanism.

It shifts gears like a regular manual car without inputs from the driver. Just like a regular manual car, the AMT also has a fixed set of gears. Every time the AMT system changes gears you can feel a sharp jerk. This jerk that occupants of the car feel as the engine revs fall dramatically when a gear is changed by the AMT system is also called shift shock.

In comparison, the CVT system has been designed to provide a smooth driving experience with linear power delivery. It works with a virtually infinite set of gear ratios and continuously changes the ratio as necessary. This is a seamless system that completely eliminates shift shock. In a CVT system, there are no traditional gears with fixed ratios to change. Think of it as a system with one gear and infinite ratios.

A company that has been at the forefront of CVT development since it was first introduced is Nissan. Over the next few pages, we’ll take a closer look at how Nissan’s CVT is not just a step up from regular AMTs, but other CVT systems as well.
 

Nissan first adopted CVT way back in 1992. A decade afterthat, it refreshed and modernised the technology. And the one it offers in India now, is at a completely different level.

Traditionally, it was believed that the more gears you have, the more efficient the transmission will be and therefore, automatics are available with anything between four and seven gears. But that isn’t the case anymore. Nissan’s Xtronic CVT can be described as a system with one gear and virtually infinite ratios. Sounds like mumbo jumbo, but we’ll explain how this works.

To simplify how a CVT works, think of gears on a bicycle. By using high and low gears, you can keep smoothly changing the amount of effort required for pedalling. In the case of a car, this would be power from an engine. The chain that drives the cycle moves between gears of different sizes to help. These are gears with fixed ratios. In a CVT system, these gears are replaced with two pulleys and a belt. By changing the width of the two pulleys it becomes possible to change gear ratio. Since there’s no separate gear, the ratios change seamlessly, i.e. without any jerks or shift shocks. That’s why a CVT system is considered to have a premium luxurious feel. Can’t say the same about AMTs now, can you?

Continuous innovation

Nissan’s CVT system though, is a step up not just from other automatic transmissions, but conventional CVTs as well. Continuous innovation from Nissan has ensured that its CVT delivers seamless shifting with constant power. It is really a next-generation automatic transmission. Nissan’s CVT is the world’s first CVT with a sub-planetary gear and has the world’s highest transmission ratio. It manages this despite being compact and 13 percent lighter than other CVTs. To ensure constant power, it is equipped with a torque converter that’s also quite compact. It has a more efficient oil pump, greater lock-up area and a design that allows for less oil stirring. What does this mean for you? It means friction in the transmission is reduced by up to 30 percent. Less friction here means more fuel efficiency. In short, all these innovations mean that Nissan’s CVT ensures you always have power without compromising on fuel efficiency. Reduced friction also means that Nissan’s CVT-equipped cars run quietly.

Does it last?

A CVT system has fewer moving parts. We’ve already established that thanks to Nissan’s intelligent design, the amount of friction in its CVT system is much lower. Lower friction means lower heat which means lower wear and tear. Then consider that Nissan’s CVT has fewer moving parts and is more compact and lighter than a traditional automatic like an AMT or even other CVTs. All of this translates into much higher durability. Don’t forget, lighter also means better performance and reduced fuel consumption. 

Nissan was one of the first to bring the Continuously Variable Transmission to India and make it a success. Today you can get the Nissan Micra and Nissan Sunny equipped with CVT transmissions.

The Nissan Micra

This dynamic, stylish and comfortable hatchback offers the advantage of a smooth, quiet Continuously Variable Transmission. The Micra also comes packed with cutting-edge technology that makes its already pleasurable driving experience even better. A button on the gear lever engages sport mode when “D” or Drive mode is active that makes this fun car even more responsive. Tight spots are also easily navigable thanks to it’s smallest turning radius.

The Micra has been designed with a host of intuitively designed conveniences like the push start-stop button, intelligent key and others that make it more enjoyable. It’s comfortable and spacious interior will definitely make you wonder how Nissan made this car seem much bigger on the inside.

The Micra also has a plethora of safety systems like dual front airbags and front seat-mounted side impact airbags, ABS, EBD and Brake Assist that provide enhanced protection while driving.
Attractive on the outside, premium, plush and comfortable on the inside, the Nissan Micra is a proper all-rounder. Add to that the practicality and convenience of Nissan’s CVT system mated to a powerful engine delivering 19.34kpl and it’s a clear winner.

The Nissan Sunny

The Nissan Sunny has many things going for it already. It is a seamless blend of design, performance and comfort. The space it offers in its class is simply superb. Whether behind the wheel, or sitting comfortably as a passenger, once you’re in the Sunny, your experience will be superlative.

Premium features, advanced tech and seamless connectivity come standard with the Nissan Sunny. Convenience and practicality abound in the Nissan Sunny. Living with it then, is very comfortable. More so, thanks to the 17.97kpl mileage. Obviously, the Sunny comes packed with safety features that are to be expected from a car of this class. Multiple airbags, ABS + EBG + BA, engine immobiliser and more, all make your journey secure.

Add to all of this the comfort, convenience and practicality of an efficient CVT system and the Nissan Sunny emerges as the car to buy. 

The Nissan CVT belt and pulley

Sounds old-fashioned but it’s actually cutting-edge tech. This system has two pulleys - an input pulley and an output pulley. The belt is made from durable steel.  As the input (engine) pulley width increases and the output (tyre) pulley width decreases, the input pulley becomes smaller than the output one. This is the state of being in low gear, such as first gear for AT. Vice versa, as the input pulley width decreases and the output pulley width increases, the diameter of the part where belt and pulley are in contact grows larger for the input pulley than the output pulley, which is the state of being in high gear (fifth or sixth for AT). One of CVT’ s strengths is that pulley width can be continuously changed, allowing the system to change transmission gear ratio smoothly and without steps. There are videos online that can explain this visually too.

The skilled Nissan CVT

As compared to an AMT where the engine revs build up and drop while changing gears, the Nissan CVT system raises engine revs quickly and maintains them in a zone that offers good fuel efficiency. This helps boost fuel economy. Even the software that controls the CVT system has been evolving. It interprets the driver’s commands through operation of the pedal and steering for optimal shift control. The new Nissan CVT is a crafty bit of engineering and if you don’t already own one, definitely go test it.
 

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