Advanced automotive transmission development status and research needs
This report summarizes the development status of advanced automotive transmissions and identifies areas where further research effort is needed. The status of conventional transmission technology is briefly examined, and the development status of continuously variable transmissions (CVTs) for automotive applications is examined in detail. Successful development of a CVT promises significant fuel economy benefits, even compared with the advanced automatic transmissions due to the improved matching of engine operating regime to vehicle requirements made possible by the continuous range of transmission ratios available with a CVT. Belt CVTs, are now well developed technology. The van Doorne CVT, which employs a multipiece steel belt, is expected to be used in production automobiles within two years. Designs based on rubber belts are also expected to appear on small cars in the middle to late 1980s. One European car line presently uses a rubber belt CVT. Hydrostatic CVTs, based on variable-displacement hydraulic pump/motor combinations, are at an advanced state of engineering development and are in production for off-road applications. Cost, weight, noise, and efficiency problems need to be solved for automotive applications. Traction CVTs, based on traction between two or more rotating elements at a variable-location contact area, are being developed by several companies for automotive applications. Automotive units are now being tested in prototype installations. Ratchet CVTs, based on variable-stroke oscillatory motion, are also being developed for automotive use. These are at a relatively early stage of development. In general, research is needed leading to more comprehensive CVT efficiency and system dynamics models and data, to facilitate comparisons of various CVTs and to aid in control system development. Specific research needs for each particular transmission type have been identified.
- Research Organization:
- Aerospace Corp., El Segundo, CA (USA)
- DOE Contract Number:
- AI01-82CS50286
- OSTI ID:
- 5150738
- Report Number(s):
- DOE/CS/50286-1; ON: DE82019265
- Resource Relation:
- Other Information: Portions of document are illegible
- Country of Publication:
- United States
- Language:
- English
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