The continuously variable transmission (CVT), which has been in use in some of
the vehicles in the market today, presents the possibility of decoupling the engine
speed and the vehicle speed. By this way, it is now possible to operate the engine
at its maximum efficient or performance point and fix it at that operating point
without losing from the vehicle speed. Instead of using gears, which are the main
transmission elements of conventional transmission, CVT uses two pulleys and a
belt. By changing the pulley diameters, a continuously variable transmission ratio
is obtained. Besides all its advantages, it has some big drawbacks like low
efficiency, torque transmission ability and limited speed range. With developing
technology, however, new solutions are developed to eliminate these drawbacks.
In this study simulation models for the performance and fuel consumption
of different types and arrangements of continuously variable transmission (CVT)
systems are developed. Vehicles, which are equipped with two different
arrangements of CVT and an automatic transmission, are modelled by using
Matlab& / #8217 / s simulation toolbox Simulink. By defining the required operating points
for better acceleration performance and fuel consumption, and operating the
engine at these points, performance optimization is satisfied. These transmissions
are compared with each other according to their & / #8216 / 0-100 kph& / #8217 / acceleration
performances, maximum speeds, required time to travel 1000 m. and fuel
consumptions for European driving cycles ECE and EUDC.
These comparisons show that CVT systems are superior to automatic
transmission, according to their acceleration and fuel consumption performances.
CVTs also provide smoother driving, while they can eliminate jerks at gear
shifting points.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/2/1095322/index.pdf |
| Date | 01 January 2003 |
| Creators | Guvey, Serkan |
| Contributors | Unlusoy, Yavuz Samim |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | M.S. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for public access |
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