See VT or CVT?
Nobody asked me but . . .
See VT or CVT?
One is an advertising campaign for visiting Vermont. The other is a type of transmission.
Do you know the difference? Do you care?
Well you should.
If you are in the market for a new car these days, you could be purchasing a CVT, which stands for Continuously Variable Transmission. What exactly is a CVT and how does it work? Here is a basic primer courtesy of the folks at Edmunds.com.
Although there are different variations on the CVT theme, most passenger cars use a similar setup. Essentially, a CVT transmission operates by varying the working diameters of the two main pulleys in the transmission. The pulleys have V-shaped grooves in which the connecting belt rides. One side of the pulley is fixed; the other side is moveable, actuated by a hydraulic cylinder. When actuated, the cylinder can increase or reduce the amount of space between the two sides of the pulley. This allows the belt to ride lower or higher along the walls of the pulley, depending on driving conditions, thereby changing the gear ratio. If you think about it, the action is similar to the way a mountain bike shifts gears, by "derailing" the chain from one sprocket to the next — except that, in the case of a CVT, this action is infinitely variable, with no "steps" between.
There is one other type of CVT which the Edmunds folks don’t mention. That would be the electronic CVT, which is used on virtually all full hybrids, such as those from Toyota/Lexus and Ford. They are even simpler and more elegant designs than the mechanical CVTs used in most other automotive applications.
The "stepless" nature of its design is a CVT's biggest draw for automotive engineers. Because of this, a CVT can work to keep the engine in its optimum power range, thereby increasing efficiency and gas mileage, especially in city driving. A CVT can convert every point on the engine's operating curve to a corresponding point on its own operating curve.
CVTs have been around for a long time . . . they date back to the 1880s. But I first heard about them in the 1960s when Daf, a Dutch automaker, introduced the transmission on some of its small, low-powered models. And I do mean low-powered. Because of limitations in the area of the materials used for the rubber belts, the engines used with these early CVTs were limited to around 1.2 liters or less.
The diminutive Subaru Justy, which was sold in the U.S. from 1989 through 1993 was offered with a CVT. There wasn’t much Justy-fication for a CVT in that tiny Subaru, but today, you’ll find CVTs handling more than 250 bhp and more than 250 lb-ft of torque hooked up to various Nissan and Audi models.
In fact, current conventional CVTers include the Ford Five Hundred and Freestyle, Mercury Montego, Audi A4 and A6, Nissan Murano, Maxima and the upcoming Versa and the Dodge Caliber.
And I’ll leave you with these questions. CVT or no CVT? Would you buy one? If you own one, do you like it? If not, why not?
My inquisitive mind would like to know.
See VT or CVT?
One is an advertising campaign for visiting Vermont. The other is a type of transmission.
Do you know the difference? Do you care?
Well you should.
If you are in the market for a new car these days, you could be purchasing a CVT, which stands for Continuously Variable Transmission. What exactly is a CVT and how does it work? Here is a basic primer courtesy of the folks at Edmunds.com.
Although there are different variations on the CVT theme, most passenger cars use a similar setup. Essentially, a CVT transmission operates by varying the working diameters of the two main pulleys in the transmission. The pulleys have V-shaped grooves in which the connecting belt rides. One side of the pulley is fixed; the other side is moveable, actuated by a hydraulic cylinder. When actuated, the cylinder can increase or reduce the amount of space between the two sides of the pulley. This allows the belt to ride lower or higher along the walls of the pulley, depending on driving conditions, thereby changing the gear ratio. If you think about it, the action is similar to the way a mountain bike shifts gears, by "derailing" the chain from one sprocket to the next — except that, in the case of a CVT, this action is infinitely variable, with no "steps" between.
There is one other type of CVT which the Edmunds folks don’t mention. That would be the electronic CVT, which is used on virtually all full hybrids, such as those from Toyota/Lexus and Ford. They are even simpler and more elegant designs than the mechanical CVTs used in most other automotive applications.
The "stepless" nature of its design is a CVT's biggest draw for automotive engineers. Because of this, a CVT can work to keep the engine in its optimum power range, thereby increasing efficiency and gas mileage, especially in city driving. A CVT can convert every point on the engine's operating curve to a corresponding point on its own operating curve.
CVTs have been around for a long time . . . they date back to the 1880s. But I first heard about them in the 1960s when Daf, a Dutch automaker, introduced the transmission on some of its small, low-powered models. And I do mean low-powered. Because of limitations in the area of the materials used for the rubber belts, the engines used with these early CVTs were limited to around 1.2 liters or less.
The diminutive Subaru Justy, which was sold in the U.S. from 1989 through 1993 was offered with a CVT. There wasn’t much Justy-fication for a CVT in that tiny Subaru, but today, you’ll find CVTs handling more than 250 bhp and more than 250 lb-ft of torque hooked up to various Nissan and Audi models.
In fact, current conventional CVTers include the Ford Five Hundred and Freestyle, Mercury Montego, Audi A4 and A6, Nissan Murano, Maxima and the upcoming Versa and the Dodge Caliber.
And I’ll leave you with these questions. CVT or no CVT? Would you buy one? If you own one, do you like it? If not, why not?
My inquisitive mind would like to know.
posted by The Carmudgeon at
7:11 PM
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