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Automobiles--Transmission devices, Continuously variable


  • URI(s)

  • Instance Of

  • Components

    • us: Transmission devices, Continuously variable Topic Component
  • Scheme Membership(s)

  • Collection Membership(s)

  • Variants

    • us: Automobiles--Gearless transmissions
    • us: Automobiles--One-speed automatic transmissions
    • us: Automobiles--Pulley transmissions
    • us: Automobiles--Single-speed transmissions
    • us: Automobiles--Variable pulley transmissions
    • us: Continuously variable transmissions, Automobile
    • us: CVTs (Continuously variable transmissions)
    • us: Gearless transmissions, Automobile
    • us: One-speed automatic transmissions, Automobile
    • us: Pulley transmissions, Automobile
    • us: Single-speed transmissions, Automobile
    • us: Variable pulley transmissions, Automobile
  • Broader Terms

  • Sources

    • found: Work cat: Nakano, M. Development of a large torque capacity half-toroidal CVT, 2000: p. 1 (This paper describes a half-toroidal continuously variable transmission (CVT) that has been newly developed. ... The ratio of cars equipped with an automatic transmission in Japan has risen in recent years to reach nearly 90% today ... . Meanwhile, the capacity of belt-driven continuously variable transmissions ... has been increased ...)
    • found: Beachley, N.H. Continuously variable transmissions, 1979: pp. 1-2 (A CVT is a transmission having a speed ratio that can be varied continuously over its allowable range. Its speed ratio may take on any value between its operational limits, i.e., an infinite number of ratios are possible. A gearbox transmission, on the other hand, has a discrete number of fixed speed ratios. The term continuously variable transmission also usually implies that torque may be controlled independently of speed ratio and vice versa. In other words, the torque converter of the conventional automobile should not be considered a CVT because the speed ratio is set by the torque transmitted. The term infinitely variable transmission (IVT) means basically the same as CVT, with the added restriction that a speed ratio of zero must be available, i.e., it must be possible to have zero output velocity for any input speed producing an infinite ratio range. A CVT providing negative as well as positive speed ratios would also be considered an IVT since its range passes through a speed ratio of zero. Even though this definition of IVT is generally accepted, IVT is often used as a synonym for CVT by those not familiar with the difference)
    • found: IEEE transactions on control systems technology, Sept. 2012: p. 1376 (Current automotive research aims at reducing emissions and fuel consumption, e.g., with advanced transmissions, like the continuously variable transmission (CVT). ... The CVT encloses a torque converter, a drive-neutral-reverse set, a variator, an actuation system, and a final drive. The variator consists of a metal V-belt ( the pushbelt), a primary pulley, and a secondary pulley. One of the conical sheaves of each pulley is axially fixed, whereas the other can move in the axial direction. Changes of the transmission ratio are achieved by simultaneous adjustment of the clamping forces on the movable sheaves. This results in an axial displacement of these sheaves and, due to this displacement, in a change of the running radii of the pushbelt on the pulleys and therefore also of the transmission ratio)
    • found: Mr. Transmission WWW home page, Mar. 14, 2017: search our library/continuously variable transmissions are gaining popularity (.... Most automatic transmissions rely on gears to operate. CVTs, on the other hand, don't have any gears at all. They operate using a system of variable pulleys connected by a belt, hence the alternative moniker, the pulley transmission)
    • found: Learn the facts: Transmission technologies and their impact on fuel consumption, via WWW, Mar. 14, 2017 (Continuously variable transmissions (CVTs) are a type of automatic transmission that do not have a specific number of fixed gear ratios but rather allow for an "infinite" number of gear ratios. This arrangement enables the engine to operate at optimal efficiency over a wider range of vehicle speeds. CVTs provide the greatest efficiency improvements in urban "stop-and-go" driving conditions. ... Date modified: 2016-01-08)
    • found: Tribology & lubrication technology, Aug. 2015: p. 88 (The need to improve the fuel efficiency of automobiles has driven the increase in the number of gears (so the engine can operate close to its peak efficiency more of the time). ... Ideally, we would like a simpler arrangement that would permit the device to vary the speed ratio continuously and seamlessly. Such a device is the continuously variable transmission (CVT). ... The CVT is known by a variety of names, including the single-speed transmission, gearless transmission, one-speed automatic, variable pulley transmission and infinitely variable transmission) [Cataloger's note: In regard to the "infinitely variable transmission" see the Beachley reference above]
  • LC Classification

    • TL264.C66
  • Change Notes

    • 2017-03-15: new
    • 2017-07-13: revised
  • Alternate Formats

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