AUTOMOTIVE CVT

A continuously variable transmission, CVT, can optimize the automotive propulsion system by allowing the engine to be operated in the most efficient manner regardless of road speed. For maximum acceleration the CVT allows the engine to run at peak power continuously rather than fluctuating with road speed, and the overall power rating of the engine can be reduced for equivalent performance. The smaller engine increases the engine load factor for normal driving, further improving the engine and propulsion system efficiency. The development of the cone roller toroidal drive (CRTD) beginning in the late 1940s, along with modern bearing steels, synthetic traction lubricants, and modern computer-based analysis of the traction contact have led to a practical, efficient, quiet, wide ratio range transmission for automotive use. The CRTD is a traction drive, not a friction drive. In traction drives, friction is as undesirable as in any modern drive. With lubricated traction, where the use of the lubricant both guards against friction and helps cool the traction elements, the actual power transmission between the contacting elements is through the resistance to shear and slip of the lubricant film under very high contact pressure. Starting with the selected 12:1 ratio range cone roller toroidal drive, a complete automotive transmission can be designed.

• Corporate Authors:

  American Society of Mechanical Engineers

  Two Park Avenue
  New York, NY  United States  10016-5990
• Authors:
  • Kraus, J H
• Publication Date: 1976-10

Media Info

• Features: References;
• Pagination: p. 38-43
• Serial:
  • ASME Journal of Mechanical Engineering
  • Volume: 98
  • Issue Number: 10
  • Publisher: American Society of Mechanical Engineers

Subject/Index Terms

• TRT Terms: Automatic transmissions; Automobiles; Continuously variable transmissions; Economic efficiency; Friction; Fuel conservation; Lubrication; Manual transmissions; Power; Propulsion; Shear strength; Slip resistance; Traction; Traction drives; Transmissions; Vehicle drive systems; Vehicle power plants
• Uncontrolled Terms: Efficiency; Propulsion systems
• Old TRIS Terms: Automobile engines; Cone roller toroidal drives; Mechanical drive
• Subject Areas: Economics; Energy; Highways; Safety and Human Factors; Vehicles and Equipment;

Filing Info

• Accession Number: 00153229
• Record Type: Publication
• Source Agency: Engineering Index
• Files: TRIS
• Created Date: Jun 17 1977 12:00AM