Leonardo da Vinci may be best-known for his Renaissance artwork, but the man was also fascinated by engineering. He designed concepts of helicopters, weapons and even engines that were hundreds of years before their time. In fact, one of his concepts ended up becoming an integral part of automotive engineering. Da Vinci originally envisioned a stepless continuously variable transmission (CVT), but the design was not perfected and patented until 1886.
Until recently, CVTs were reserved for industrial machinery. A Dutch car company produced a car with a CVT in 1958, but it wasn't until 1989 that CVTs began to take off in the U.S. with the introduction of the Subaru Justy GL.
What is it exactly that sets the CVT apart from a conventional automatic transmission? Well, a vehicle's transmission is designed to control the speed ratio between the engine and the wheels. A traditional automatic transmission controls a set of gears that engage and disengage as needed, much like a manual transmission, but in the case of a CVT, the gears are replaced by a pulley system.
This allows for infinite gear ratios, rather than just four or five, as is typical in a manual or traditional automatic setup. With a continuously variable transmission, the engine is able to transition through the gears without any noticeable shifts. While the engine will race the way it would in a car with a slipping clutch or a faulty transmission, this is just the sound of the CVT adjusting itself to provide optimal power.
Cars with CVTs tend to accelerate more slowly, but they do so fluidly. The RPMs do not jump around as they do in manual or traditional automatic transmissions, which allows for a smoother drive. They are also better at handling hills, because they can adjust the gear ratio as needed to find the ideal setting. A regular automatic transmission will struggle to find the right gear for making the ascent.
CVTs used to be lacking a bit in the power department, which may explain why it has taken American drivers so long to embrace the technology. Now, they are lighter and better able to handle larger, more powerful engines. They also improve fuel economy and give cars more control over emissions.