I think my transmission is Broken!
When some people start to drive a car like a Nissan Versa with a Constant Velocity Transmission (CVT), they bring it back to their dealer thinking that there’s something wrong with it. You see, we’re all used to hearing and feeling a transmission shifting as we accelerate.
When you drive a car with a CVT, you aren’t even aware that the transmission is actually changing gears. Well, maybe changing gears isn’t exactly the right expression. Changing gear ratios is more accurate. In fact, Nissan is working on a CVT that simulates the sensation of changing gears to make drivers who aren’t used to a CVT more comfortable.
An old idea that’s come of Age
While you might think that the CVT is a relatively newfangled technology, the idea was actually conceptualized by Leonardo Da Vinci 500 years ago. The first patent for a toroidal CVT transmission was issued in 1886. The CVT has long been used on scooters, snowmobiles, and tractors. In 1989, the Subaru Justy was the first car on US roads with a CVT. The Honda Civic HX used a CVT during the late 90’s, and the Saturn Vue hit the streets with a CVT in 2002. Since then, the technology has been continually improved and now that the concept has come of age, it’s appearing on more and more vehicles.
Here’s how it Works
A typical CVT uses two variable diameter pulleys consisting of two opposing 20 degree cones with a heavy duty rubber and Kevlar or steel belt running around them. One pulley is attached to the engine (input), and the other is attached to the drive wheels (output). As the engine rpm’s change, the halves of the pulleys move apart and as the belt slides up and down between them, the gear ratio constantly changes. To better understand the concept, picture changing the gears on your old 10 speed bike. As the chain moved up and down the toothed cogs attached to the rear wheel and the pedals, the gear ratio changed. A CVT can produce a virtually unlimited number of gear ratios and strike a perfect balance between engine speed and fuel efficiency.
Driving with a CVT
One thing that most drivers notice immediately when they drive a vehicle with a CVT is they don’t hear or feel the transmission changing gears. Acceleration is also very smooth in a vehicle equipped with a CVT. On hills, a CVT powered car doesn’t have to hunt for the right gear – it finds the perfect gear ratio. When you step on the gas pedal of a car with a CVT, the engine races momentarily and to some people it feels disconcertingly like a clutch is slipping. Then, the belt engages with the pulleys and the vehicle begins to smoothly accelerate away.
When you press hard on the gas pedal in a car with a traditional transmission, it lurches and then accelerates hard, changing gears as it goes. A CVT provides smooth, steady acceleration. While it feels slower to some drivers, cars with a CVT can actually accelerate quicker than a car with a conventional transmission. What about gas mileage? One of the major selling points of a vehicle with a CVT is their fuel efficiency.
Disadvantages of a CVT
While CVT’s have been common in Europe for decades, they’re new to most drivers in North America. Some drivers find driving a car with a CVT unsettling until they get used to it not making gear changes that they can hear or feel. In fact, some CVT’s offer a manual mode with paddle shifters on the steering wheel that give the driver the illusion that they are shifting gears.
The RPM’s of engines equipped with a CVT can fluctuate wildly, something else that some drivers find difficult to get used to. If the belt breaks in a CVT, the entire transmission is usually replaced (fortunately, that’s a very uncommon occurrence). That can be very expensive if it isn’t covered under warranty. Not all CVT’s are suitable for towing and they aren’t usually paired with high horsepower, high torque engines.
If you want neck snapping acceleration and smoking tires, a CVT might not satisfy your need for speed.
Nissan leads the Way
While a CVT is not suitable for some applications, if your priorities are fuel efficiency and an extremely smooth running transmission, a vehicle with a CVT might be right for you. You be the judge – test drive a vehicle with a CVT transmission at Kelowna Nissan today!