The CVT or Continuously Variable Transmission have been the preferred choice of the automatic transmission for many automakers. These belt-driven transmission systems are known for their comparatively seamless gear changes with the advantage of infinite gear ratios, and that translates down to refined ride quality. The rpm levels remain more constant and the engine remains relaxed, at varying speeds, and that makes CVT fitted vehicles quite fuel-efficient as well. [3]

Figure 1. Pros and Cons of Continuously Variable Transmission (CVT)

Figure 1 shows while a traditional transmission uses a wide variety of intricate parts to shift between a range of preset gears, most CVT systems work through a pulley system. In short, this system consists of cones at each pulley connected via a chain belt. The cones can move to increase or decrease the belt diameter to change gear ratios, allow for quick shifting into the needed ratio for increased power, and boost fuel economy.

One pulley in the CVT is connected to the engine and the other directs power to the wheels. The width of these pulleys changes based on the needed power; as one gets larger, the other gets smaller. This allows a CVT to deliver strong and seamless acceleration as explained by CarFax. [2]

CVT Pros and Cons

Automakers increasingly use CVTs due to several benefits they provide:

• Increased fuel economy. CVTs are more efficient than standard automatic transmissions and are commonly utilized in hybrid powertrains and smaller cars to maximize the number of miles you can travel on every gallon of gas.
• Responsive acceleration. Due to its variable characteristics, a CVT can typically find the proper gear ratio much faster than an automatic transmission at virtually every speed ranging from off-the-line to highway passing.
• Smoother driving character. The absence of hard shift points means a CVT delivers more consistent performance across the engine's rev band. There are no abrupt downshifts or lags in acceleration as experienced with automatic and manual transmissions.

While CVTs offer some clear advantages for certain car owners, they are not for everyone. Some drawbacks include:

• Lack of character. There is little to no shifting feel which results in a driving experience that can be bland and uninteresting.
• Noisiness. Many drivers find CVTs to be louder and whinier than traditional automatic transmissions. Under hard acceleration, such as when entering a freeway, they tend to drone. This trait contributes to a less enjoyable driving character.
• Lack of high-performance capability and durability. Although CVTs offer better than average acceleration in everyday driving situations, they are not ideal for high horsepower applications or sustaining high speeds. For that reason, CVTs are typically not utilized in sports cars.
• Higher repair costs. Not only do CVTs cost more to fix or replace, they generally do not last as long as traditional automatic transmissions. [1]

The ATM33 series is available in three packages: a 5×5 40-pin QFN, a 7×7 56-pin QFN, and a wafer level chip scale packaging (WLCSP) for ultra-compact applications. Sampling will be available in Q1 2022. [1]

References:

1. https://www.jdpower.com/cars/shopping-guides/what-is-a-cvt-or-continuously-variable-transmission
2. https://www.caranddriver.com/research/a30822055/what-is-a-cvt-transmission/
3. https://www.91wheels.com/news/pros-and-cons-cvt

Cite this article:

Thanusri swetha J (2022), Pros and Cons of Continuously Variable Transmission (CVT), pp. 109